This is an extension of a presentation I gave to the Ozark Mountain Gem & Mineral Society on 25 April 2022. Please click on the images to view copyright information.
10 Most Deadly Minerals
There are dozens of “# (pick a number) Most (insert favorite doom and gloom word here) Mineral” lists available on the internet. Nearly all of them have some combination of the following minerals listed:
I’m going to attempt to clear up some of the misconceptions in these types of articles from the authors making incorrect assumptions about toxic elements. I’ll do this by giving an in-depth introduction to how toxicity works and which types of minerals are a risk to mineral enthusiasts.
What is Toxicity?
Merriam-Webster defines toxicity as “an extremely harsh, malicious, or harmful quality.” Many of the same elements in minerals are ones our bodies need to work properly, but in large quantities can be damaging. Others have negative effects no matter how small the dose. A significant number of both of these types of elements are considered heavy metals, which just means they have a higher density and atomic weight than other elements.
![This table shows the number of heavy metal criteria met by each metal, out of the ten criteria listed in this section i.e. two based on density, three on atomic weight, two on atomic number, and three on chemical behaviour. It illustrates the lack of agreement surrounding the concept, with the possible exception of mercury, lead and bismuth. Six elements near the end of periods (rows) 4 to 7 sometimes considered metalloids are treated here as metals: they are germanium (Ge), arsenic (As), selenium (Se), antimony (Sb), tellurium (Te), and astatine (At).[16][n 2] Oganesson (Og) is treated as a nonmetal. Metals enclosed by a dashed line have (or, for At and Fm–Ts, are predicted to have) densities of more than 5 g/cm3.](https://i0.wp.com/sisyphos.rocks/wp-content/uploads/2022/04/Heavy-Metals.jpg?resize=504%2C367&ssl=1 "Heat map of heavy metals in the periodic table")
Heat map of heavy metals in the periodic table
This table shows the number of heavy metal criteria met by each metal, out of the ten criteria listed in this section i.e. two based on density, three on atomic weight, two on atomic number, and three on chemical behaviour. It illustrates the lack of agreement surrounding the concept, with the possible exception of mercury, lead and bismuth. Six elements near the end of periods (rows) 4 to 7 sometimes considered metalloids are treated here as metals: they are germanium (Ge), arsenic (As), selenium (Se), antimony (Sb), tellurium (Te), and astatine (At).[16][n 2] Oganesson (Og) is treated as a nonmetal. Metals enclosed by a dashed line have (or, for At and Fm–Ts, are predicted to have) densities of more than 5 g/cm3.
How Does Toxicity Work?
There are a couple of ways that toxic minerals interact with the body to produce negative effects:
- Lose one or more electrons, forming a metal cation, binding to macromolecules, and disrupting the important biological process resulting in:
- Gastrointestinal or kidney disfunction
- Nervous system disorders
- Skin lesions
- Vascular damage
- Immune system dysfunction
- Birth defects
- Cancer
- Generate reactive oxygen species, disrupting DNA synthesis and repair
- Neuropsychiatric disorders
- Enzyme inactivation
- Suppression of antioxidant defense
Basic Notions of Toxicology
Table of Contents
- Dose
- Bioavailability
- Acute Toxicity
- Chronic Toxicity
- Changes in the Body
- Radiotoxicity
- Radioactive Mineral Hosts - Uranium
- Radioactive Mineral Hosts - Thorium
- Radioactive Minerals
- Preventative Measures
- Physical Toxicity
- Coal
- Asbestos
- Silica
- Preventative Measures
- Chemical Toxicity
- Skin Contact
- Preventative Measures
- Ingestion
- Preventative Measures
- Inhalation
- Preventative Measures
- Fluorides / Fluorophosphates
- Oxidizing Agents
- Sulfides
- Preventative Measures
Dose
Nearly everything is harmful in big enough doses, but how often and how long you are exposed along with how you are exposed make a significant difference in how toxic it will be to you.
Bioavailability
Bioavailability is one of the most important notions in mineral toxicity. It refers to how much of the toxic element reaches the circulatory system. While there are a number of elements that have been found in their native state, only gold, silver, copper, and the platinum group (platinum, iridium, osmium, palladium, rhodium, ruthenium) can be found in large amounts. Normally elements bind to another element within the mineral, changing its properties.
For instance, sodium (Na) is a highly volatile metal. When water contacts it, it explodes by spontaneously producing hydrogen (H) and sodium hydroxide (NaOH). NaOH is highly caustic and will cause severe burns even though the explosion causes a relatively minor fire. Because sodium is so volatile, it’s never found naturally in its native state. It always forms compounds with other elements.
.jpg "Sodium (Na)")
Sodium (Na)
© Petr Fuchs
Chlorine (Cl) is an extremely reactive gas and a strong oxidizing agent. It is poisonous to most living organisms and was used for chemical warfare during World War I. Because of its extreme reactivity, there are no natural sources of native chlorine. It also always forms compounds with other elements.
Sodium chloride (NaCl) is the most common compound of either chlorine or sodium. It is the 21st most abundant chemical in Earth’s crust and third most abundant in seawater. Sodium chloride is an essential component to life for its use in nerve impulse generation and electrolyte and fluid balance.
Sodium chloride is commonly called “salt.” While too much salt in your diet is harmful, you can’t live without it. So even though a mineral might contain a harmful element, more than likely that element is part of a compound that is not dangerous.
For a mineral to be bioavailable, there are two things that must be true.
- It is water- or acid-soluble (or both)
- It can be broken down before it leaves your body
Water/acid-soluble minerals chemically react with the water and/or acids in your body, breaking compounds’ elemental bonds and forcing the elements apart or forming one or more new compounds. These elements/compounds now have access to the circulatory system. Some of these elements/compounds can bind to enzymes (resulting in their loss of function) or to DNA/RNA (disrupting their ability to produce proteins or replicate cells), which is what makes them toxic. They disrupt the normal functioning of the body producing side effects.
(If you’re asking yourself why salt, which is water-soluble, doesn’t explode when it’s mixed with water, I found a video on YouTube explaining why. When salt dissolves in water, the water does break the salt’s elemental bonds. But when the sodium and chlorine chemically combined originally, the sodium gave one of its electrons to the chlorine. When water breaks them apart, the chloride ion keeps that extra electron, making both the sodium ion and chloride ion more stable than their native elements.)
Acute Toxicity
Acute toxicity refers to the capacity to produce harmful effects from a single dose in a relatively short time, from minutes to about two weeks. Testing is normally done on rats or mice, so dosage information is approximated by taking the amount of material that caused the reaction per tested animal’s body weight and scaling it up for humans.
- Median Lethal Dose LD50 (oral/skin – mg/kg of body weight) or LC50 (inhalation – mg/m3 of air for solids, ppm for gases): dose that kills 50% of tested animals
- Lowest Lethal Dose LDLo / LCLo: lowest dosage known to have killed an animal
- Lowest Toxic Dose TDLo / TCLo: lowest dosage known to have resulted in any kind of toxic effect other than death
The Acute Toxicity Rating System breaks this out into:
- Highly Toxic: LD50 < 50mg/kg
- Toxic: 50mg/kg < LD50 < 100 mg/kg (not in official system, but necessary for very dense metals/metalloids)
- Moderately Toxic: 100 mg/kg < LD50 < 500 mg/kg
- Low Toxicity: LD50 > 500 mg/kg
Chronic Toxicity
Acute toxicity refers to the short-term effects of a single exposure to a toxic mineral. Chronic toxicity is the long-term effects of multiple, smaller exposures as the poison builds up on the body.
Changes in the Body
- Carcinogenic: causes cancer
- Mutagenic: causes genetic mutations
- Reprotoxic: damages the reproductive process
Risk Assessment
People who work in the mining and stone industries are at a much higher risk than mineral collectors. If you only handle solid pieces, your risk is very low. Your biggest concerns will be cleaning minerals and accidental ingestion by small children or animals. Those that do lapidary work will need to be concerned about inhalation and ingestion of rock and mineral dust as well.
Types of Toxicity
Radiotoxicity
Radioactive minerals are extremely rare. While there are a number of radioactive elements, radium, thorium, and uranium are the most common found in highly radioactive minerals. Sometimes in minerals containing rare-earth elements (REE) , the REE may be replaced by thorium, or more rarely, uranium, making them radioactive.
Radon is a byproduct of radioactive mineral decay and is radioactive itself. Radon gas is already in your homes from natural sources seeping into the tiny cracks in your home. If you plan to store radioactive minerals, it would be a good idea to keep a radon detector in your home to monitor buildup. Radon gas is heaver than air, but unlike carbon monoxide, it does not sink and stay low to the ground. It’s easily moved by the air currents in your house.
How Radon Enters Your Home
Source: EPA
These are the rare-earth elements:
Radioactive minerals are most frequently found in these types of rocks:
Radioactive Mineral Hosts - Uranium
| Igneous Rocks | Abundance | Metamorphic Rocks | Abundance | Sedimentary Rocks | Abundance |
|---|---|---|---|---|---|
| Syenites and phonolites | 0.1–26 ppm | Low-grade | <1–5 ppm | Shales, clays, mudrocks | 1–5 ppm |
| Granites and rhyolites | 2–50 ppm | Medium-grade | <1–5 ppm | Black shales (organic-rich) | 2–1250 ppm |
| Intermediate Rocks | 1–6 ppm | High-grade | <1–7 ppm | Phosphorite-black shales | ≤700 ppm |
| Basalts and other mafic rocks | 0.1–1 ppm | Sandstones | 0.5–4 ppm | ||
| Ultramafic | 0.001–1 ppm | Limestones, dolomites | <0.1–9 ppm | ||
| Coals, lignites, peats | 1–6000 ppm | ||||
| Pure evaporates | <0.1 ppm |
Radioactive Mineral Hosts - Thorium
| Igneous Rocks | Abundance | Metamorphic Rocks | Abundance | Sedimentary Rocks | Abundance |
|---|---|---|---|---|---|
| Syenites and phonolites | 0.7–35 ppm [typically >10 ppm] | Highly variable, typically | 6–10 ppm | Shales, clays, mudrocks | 10–13 ppm |
| Granites, rhyolites and intermediate igneous rocks | 8–56 ppm | Pelagic clays and siliceous oozes | 2–30 ppm | ||
| Basalts and other mafic rocks | 0.1–4 ppm | Sandstones | 1–7 ppm | ||
| Ultramafic | <0.1 ppm | Phosphorites | 1–5 ppm | ||
| Limestones, dolomites | <0.05–3 ppm | ||||
| Bauxites | ~50 ppm |
Radium comes from Radian Barite.
Radian Barite
© Petr Fuchs
Radioactive Minerals
This is a non-exhaustive list of minerals containing significant amounts of radioactive isotopes of elements, uranium and thorium. They emit alpha, beta, and gamma ionizing radiations, as well as radon.
There are three concerns with collecting radioactive minerals.
- Direct radioactivity from the minerals
- Fine radioactive dust particles
- Radon gas produced by the minerals
Irradiated Gemstones
Finally, many gemstones are irradiated to enhance or change the color. This can make them slightly radioactive. If you have concerns about wearing irradiated jewelry, make sure to purchase them from a legitimate source that is subject to the United States Nuclear Regulatory Commission and don’t wear it as your every day jewelry. Do not trust the sellers on eBay or Etsy, especially those from overseas. One sent me an irradiated gemstone as a “free” gift that is much more radioactive than normal.
Irradiated Gemstone
© Angel Doran
Preventative Measures
Keep distance or a barrier between you and the material
- Avoid handling as much as possible
- Use handling equipment when possible
- Work at arms’ length
- Wash your hands after handling the material
- Wear nitrile gloves when handling the material
Smaller specimens have less radioactive material
- Keep your specimen as small as you can
- Keep highly active, large or stock specimens in shielded storage
Do not allow the material to get inside your body
- Do not handle the material near food or drink or where they are prepared or eaten
- Do not lick, sniff, or eat the material
- Do not cut, grind, or polish the material
- Keep the material in a closed container and locked away
- Keep material away from children / pets
The build-up of radon gas is a concern
- Typical house ventilation is sufficient for small specimens
- Vent your container away from your face before opening
Physical Toxicity
The three types of physical toxicants are:
Coal
Coal workers’ pneumoconiosis or black lung disease is caused by long-term exposure to coal or graphite dust and is not a concern for mineral collectors.
Asbestos
Asbestos is a group of six naturally occurring minerals made up of heat-resistant fibers. Asbestiform minerals are ones that form into microscopic fibers and include non-asbestos minerals.
Asbestos is most frequently found in: serpentinites, altered ultramafic rocks, and some mafic rocks.
Asbestos minerals are frequently embedded within other minerals trapping the microscopic fibers. For instance, Tiger’s and Hawk’s Eye contain crocoidolite, but it’s embedded within the quartz, so the asbestos itself is not a concern (see below for quartz toxicity).
Prolonged or repeated inhalation of microscopic fibers can lead to asbestosis, mesothelioma, or lung cancer. As long as you aren’t storing large quantities of asbestiform minerals, you should be safe.
Asbestos / Asbestiform Minerals
This is a non-exhaustive list of asbestos/asbestiform minerals.
Silica
Silica occurs in three different forms:
- Crystalline
- Microcrystalline (aka cryptocrystalline): minute quartz crystals bonded together with amorphous silica
- Amorphous: non-crystalline
Crystalline Silica Minerals
Crystalline silica forms in seven different ways depending on the temperature of formation. The main three are:
Quartz is found in nearly all acid igneous, metamorphic, and sedimentary rocks. Cristobalite occurs in acidic volcanic rocks. Tridymite occurs in cavities in felsic volcanic rocks.
Prolonged or repeated inhalation of crystalline silica dust can lead to silicosis or lung cancer as the crystals get trapped in the smaller spaces of the lungs. Silicosis is a form of pneumoconiosis marked by inflammation and nodular lesions in the upper lobes of the lungs.
Signs and symptoms of silicosis include:
- Dyspnea (shortness of breath)
- Cough
- Fatigue
- Tachypnea (rapid breathing)
- Loss of appetite and weight loss
- Chest pain
- Fever
- Gradual darkening of skin
- Gradual dark shallow rifts in nails
- Cyanosis, pallor
- Cor pulmonale (right ventricle heart disease)
- Respiratory insufficiency
- Death
The microcrystalline and amorphous varieties do not pose this same hazard (though it is possible for heated amorphous silica to convert to tridymite or cristobalite). Non-crystalline silica doesn’t get trapped in the lungs like the crystalline does and the microcrystalline versions are compacted and trapped within amorphous silica.
Microcrystalline version of quartz include:
Preventative Measures
Asbestos
- Keep out of reach of children and animals
- Do not lick, ingest, or sniff
- Do not generate dust by cutting, grinding, or polishing
- Do not put your hand to your face or eat/drink/smoke while manipulating samples
- Wash your hands immediately after handling
- Store specimens in airtight containers and ventilate outdoors
Silica
- Wet cut, grind, and polish quartz and quartz-rich rocks
- Work with these outside your home in a well-ventilated area
- Keep the workspace wet to prevent dust from going airborne
- Wear an N95 respirator
- Wear disposable clothes or wash them immediately
- Shower before entering your home
Chemical Toxicity
Three routes of entry into the body are of concern for chemical elements:
- Skin Contact
- Ingestion
- Inhalation
Skin Contact
For skin absorption, highly water-soluble toxic minerals are the only type you really need to worry about. None of the toxic minerals that have bioavailable toxic elements are used as gemstones. If you plan to wear or carry (for instance, as a worry stone) something a little more unusual, make sure to look up whether it is safe.
Highly Water-Soluble Toxic Minerals
Preventative Measures
- Keep away from water or moisture
- Wear gloves when handling
- Wash hands thoroughly after handling
Ingestion
Hopefully mineral collectors aren’t prone to eating their rocks, but in the case of accidental ingestion by children or animals, here are the most toxic elements in order of toxicity and their associated bioavailable minerals, also in order of toxicity.
Preventative Measures
- DON’T LICK ROCKS!
- Don’t eat rocks!
- Wash hands thoroughly after handling and keep away from food preparation and eating areas
Inhalation
Dust inhalation is a huge risk for anyone who cuts, grinds, or polishes rocks. When metals are heated, including by cutting, grinding, or polishing, they form metal oxides. As dust, these metal oxides get trapped in the lungs’ bronchioles and alveoli, greatly increasing exposure times to minerals.
When this happens, the body produces an inflammatory response and those minerals can act as a catalyst to transform the oxygen you breathe into reactive oxygen species (ROS). ROS (superoxide anion radical, hydrogen peroxide, hydroxyl radical, and singlet oxygen) are a natural byproduct of metabolizing oxygen. They have roles in cellular functioning, like programmed cell death and host defense. ROS do this by breaking DNA strands and destroying proteins. Your body has a low level of ROS at all times, but when production increases your body goes into oxidative stress. Oxidative stress is when your body cannot clear the ROS quickly enough to repair the damage it causes to cells. This leads to inflammation, scarring, or cancer.
The reactive oxygen species can also chemically react with the metal oxides producing more dangerous water-soluble metal oxides that can move past cell membranes and into the circulatory system.
| Element | Dose | Effect |
|---|---|---|
| Antimony | Gastrointestinal irritation | |
| Arsenic | Respiratory irritation and mucous membrane damage leading to rhinitis, pharyngitis or laryngitis, nasal septum perforation | |
| Barium | >4.4 mg/m3 | Bronchial, nasal, and dermal irritant |
| Beryllium | above 100 µg/m3 | Acute beryllium disease - rhinitis, pharyngitis, tracheobronchitis, severe pulmonary disease, shortness of breath, malaise, anorexia, weight loss, coughing, cyanosis, tachypnea, tachycardia, death |
| Cadmium | 0.5 mg Cd/m3 | Metallic taste, headache, dyspnea, chest pains, cough with foamy or bloody sputum, muscular weakness, pulmonary edema, kidney and or/ liver damage, death |
| Chromium | <0.01 mg/m3 | Nasal ulcers, perforation of the nasal septum |
| Copper | 0.075 to 0.12 mg/m3 | Metal fume fever - eye and respiratory tract irritation, headaches, vertigo, drowsiness, chills, fever, aching muscles, dry mouth and throat |
| Lead | Concentration of lead in blood is used to measure exposure and cannot be described in terms of route specificity | Loss of appetite, metallic taste, constipation, obstipation, pallor, malaise, weakness, insomnia, headache, irritability, pain in muscles and joints, fine tremors, colic, Burton's lines, severe brain damage, convulsions, coma, death |
| Lithium | 0.50-1.0 mg/m3 | Severe eye, nasal, and skin irritation, cough, pulmonary lesions |
| Manganese | Metal fume fever - eye and respiratory tract irritation, headaches, vertigo, drowsiness, chills, fever, aching muscles, dry mouth and throat | |
| Mercury | 1.1 to 44 mg/m3 | Corrosive bronchitis, shock, renal disorders, lethargy, insomnia, loss of memory, excitability, chest pains, dyspnea, cough, hemoptysis, metallic taste, sore gums, excessive salivation, interstitial pneumonitis, death |
| Nickel | 7 mg/m3 | Headache, nausea, vomiting, chest pain, hyperpnea, cyanosis, respiratory failure, death |
| Selenium | Irritation of the mucous membranes of nose & throat, coughing, nosebleed, loss of smell, dyspnea, bronchial spasms, bronchitis, chemical pneumonia | |
| Silver | Acute respiratory tract irritation | |
| Vanadium | 0.1 to 85 mg/m3 | Eye and respiratory tract irritation, coughing, wheezing, rhinorrhea, sore throat, chest pain, bronchospasms, bronchitis |
| Zinc | 15 mg/m3 | Metal fume fever - eye and respiratory tract irritation, headaches, vertigo, drowsiness, chills, fever, aching muscles, dry mouth and throat |
These are some of the more common minerals containing each of these metals:
Preventative Measures
- Use an N95 respirator in a well-ventilated area
- Water cut, grind, and polish
- Do not dry vacuum
Cleaning Minerals
One last category of concern is chemical reactions when cleaning minerals with acids.
Fluorides / Fluorophosphates
When combined with acids, fluorides or fluorophosphates will yield hydrofluoric acid (HF). This can cause severe burns and is very toxic by ingestion, inhalation, and skin contact. HF will etch glass and eat through glass beakers.
Common fluorides/fluorophosphates include:
Oxidizing Agents
When hydrochloric acid comes into contact with strong oxidizing agents, chlorine gas is produced. Chlorine gas is poisonous to nearly all animals (and was used in World War I as a poison gas).
Common oxidizing agents:
Sulfides
When sulfide minerals are combines with strong acids, a toxic gas (hydrogen sulfide or nitrogen dioxide) is produced.
Common sulfides:
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Preventative Measures
- Always clean minerals with the least dangerous method first and check to ensure your intended cleaning method is safe for the mineral you are cleaning
- Clean minerals in a well-ventilated area
- Always add acid to water, not water to acid
- Label the container and do NOT seal it
- Wear protective gloves / goggles / apron
- Neutralize acids after cleaning minerals and dispose of them properly
10 Most Deadly Minerals Debunked
So here is that list of minerals frequently found on the most dangerous minerals lists. Let’s talk about why or why not each one should be on the list.
Actinolite
Reason it’s on the list: Asbestos
Actinolite, chrysotile, crocidolite, erionite, and riebeckite are asbestos or asbestiforms. Asbestos minerals are frequently co-located and trapped within other minerals, making them safe.
Take care not to inhale the tiny fibers from any fibrous mineral.
Should it be on the list: No
Arsenopyrite
Reason it’s on the list: Contains arsenic
The arsenic in arsenopyrite is not soluble in water or HCl, so is not dangerous. There are rumors of arsenopyrite with a white coating of arsenic, which would be very toxic. Any unknown crust, coating, powder, or other substance on a mineral should be considered toxic. Don’t use a strong acid to clean it.
Should it be on the list: No
Chalcanthite
Reason it’s on the list: Water-soluble copper mineral
Chalcanthite is water- and HCL-soluble. The copper in Chalcanthite is very bioavailable and toxic to plants. In high enough quantities, it can be toxic to people and animals too. For ingestion, it only takes a small quantity to be dangerous and will cause immediate vomiting. Immediately seek medical attention!
Should it be on the list: Yes
Chrysotile
Reason it’s on the list: Asbestos
Actinolite, chrysotile, crocidolite, erionite, and riebeckite are asbestos or asbestiforms. Asbestos minerals are frequently co-located and trapped within other minerals, making them safe.
Take care not to inhale the tiny fibers from any fibrous mineral.
Should it be on the list: No
Cinnabar
Reason it’s on the list: Contains mercury
Cinnabar contains mercury and like galena, but is virtually insoluble and is safe. It can decompose thermally releasing a toxic vapor and its dust is toxic. NEVER heat, or dry cut, grind, or polish cinnabar!
Should it be on the list: Yes
Coloradoite
Reason it’s on the list: Contains mercury and tellurium
Mercury telluride is not soluble in water or HCl and causes no risk. Additionally, it’s really rare.
Should it be on the list: No
Crocidolite
Reason it’s on the list: Asbestos
Actinolite, chrysotile, crocidolite, erionite, and riebeckite are asbestos or asbestiforms. Asbestos minerals are frequently co-located and trapped within other minerals, making them safe.
Take care not to inhale the tiny fibers from any fibrous mineral.
Should it be on the list: No
Erionite
Reason it’s on the list: Asbestos
Actinolite, chrysotile, crocidolite, erionite, and riebeckite are asbestos or asbestiforms. Asbestos minerals are frequently co-located and trapped within other minerals, making them safe.
Take care not to inhale the tiny fibers from any fibrous mineral.
Should it be on the list: No
Fluorite / Fluorspar
Reason it’s on the list: Contains fluorine
Fluorine is pretty nasty by itself. But when fluorine bonds to calcium, it is no longer bioavailable. Still, don’t clean it with a strong acid.
Should it be on the list: No
Galena
Reason it’s on the list: Galena contains lead and sulfur.
Chemically bonded lead sulfide, is virtually insoluble in water and only slightly soluble in hydrochloric acid and thus is unlikely to cause issues. It is an inhalation risk for both lead and nickel. Do not clean it with strong acids.
Should it be on the list: Yes
Hutchinsonite
Reason it’s on the list: Lead and thallium
Thallium poisoning is pretty awful, but this mineral has very low bioavailability and is rare.
Should it be on the list: No
Hydroxylapatite
Reason it’s on the list: Some people think that because it contains the same material as bone, it can cause blockages in your arteries (no, not at all)
This is soluble in hydrochloric acid, but breaks down into calcium and phosphoric acid, which reside in your body naturally. A very large amount might give you kidney stones, but that’s about it.
Should it be on the list: No
K-Feldspar
Reason it’s on the list: Potassium has a radioactive isotope
It’s about as radioactive as a banana.
Should it be on the list: No
Orpiment
Reason it’s on the list: Contain arsenic and sulfur
When arsenic is chemically bonded to sulfur, it is far less soluble than native arsenic. Orpiment is slightly soluble, so take care. Realgar is not at all. BUT, when it is exposed to sunlight, it can turn into pararealgar, which has a dusty coating that is dangerous to inhale.
Should it be on the list: No
Phenakite
Reason it’s on the list: Believed to cause silicosis
While Phenakite is visually similar to quartz, it’s make-up is different enough that it is not know to cause silicosis, but the beryllium in it can cause other inhalation issues.
Should it be on the list: No
Pyrite
Reason it’s on the list: May contain arsenic
Pyrite is not soluble in water or hydrochloric acid, so it poses no handling or ingestion risk. Do not clean it with a strong acid though.
Should it be on the list: No
Quartz
Reason it’s on the list: Can cause silicosis
Inhalation of crystalline silica from quartz dust can cause silicosis.
Should it be on the list: Yes
Riebeckite
Reason it’s on the list: Asbestos
Actinolite, chrysotile, crocidolite, erionite, and riebeckite are asbestos or asbestiforms. Asbestos minerals are frequently co-located and trapped within other minerals, making them safe.
Take care not to inhale the tiny fibers from any fibrous mineral.
Should it be on the list: No
Stibnite
Reason it’s on the list: Contains antimony and sulfur
Antimony sulfide is nearly insoluble and poses no risk. The dose of antimony even needed to kill a rat is between 500 and 20,000 mg/kg. That’s roughly 0.2 – 4 lbs in a 220 pound person. Don’t clean it with strong acids.
Should it be on the list: No
Uraninite
Reason it’s on the list: Radioactive
Uraninite is a radioactive mineral and you should take precautions to protect yourself from harmful radiation and radon gas.
Should it be on the list: Yes
Torbernite
Reason it’s on the list: Radioactive
Torbernite is a radioactive mineral and you should take precautions to protect yourself from harmful radiation and radon gas.
Should it be on the list: Yes
Zircon
Reason it’s on the list: It’s radioactive
Zircon may be mildly reactive, but only the ones with an unusual, amorphous appearance. These aren’t typically used in jewelry.
Should it be on the list: No
Most Deadly Mineral Types
It really depends on what you are doing with a mineral as to how dangerous it is and it is rare that a single mineral will be dangerous compared to the entire group. By picking on specific minerals, those # Most (pick an adverb) Lists don’t convey an accurate risk assessment. So here is my take on what types of minerals are dangerous depending on what you do as a collector.
Handling
Radioactive Minerals
All types of radioactive minerals (and irradiated gemstones) should be handled with care. If you collect this type of mineral, it would be handy to own a Geiger counter to roughly identify how much care you need to take with each one.
Asbestos
The asbestos fibers in these minerals are microscopic. It’s best to keep them in a air-tight container and not handle them.
Water-Soluble Minerals
Keep highly water-soluble minerals away from moisture and water, including sweat from your hands.
Cleaning
- Fluorides / Fluorophosphates
- Oxidizing Agents
- Sulfides
Cutting, Grinding, Polishing
- Silica minerals
- Minerals containing any of the following:
- Antimony
- Arsenic
- Barium
- Beryllium
- Cadmium
- Chromium
- Copper
- Lead
- Lithium
- Manganese
- Mercury
- Nickel
- Selenium
- Silver
- Vanadium
- Zinc
Accidental Ingestion
- Water- /acid-soluble minerals
References
- Balali-Mood, Mahdi, Naseri, Kobra, Tahergorabi, Zoya, Khazdair, Mohammaf Reza, and Sadeghi, Mahmood. “Toxic Mechanisms of Five Heavy Metals: Mercury, Lead, Chromium, Cadmium, and Arsenic“. Frontiers in Pharmacology. 13 April 2021. https://www.frontiersin.org/articles/10.3389/fphar.2021.643972/full
- DeWitt, Tyler. “Sodium Explodes in Water…Why Doesn’t Salt?!?” 29 April 2015. https://www.youtube.com/watch?v=CArZeDTwVh4
- Doelman, CJ, Leurs R, Ossterom, WC, and Bast, A. “Mineral dust exposure and free radical-mediated lung damage“. 16 January 1990. https://pubmed.ncbi.nlm.nih.gov/2407528/#:~:text=Abstract,release%20of%20reactive%20oxygen%20species.
- Freedman, Bill. “Environmental Science: A Canadian Perspective”. 6th Edition. Chapter 18 – Toxic Elements. https://ecampusontario.pressbooks.pub/environmentalscience/chapter/chapter-18-toxic-elements/
- Fubine, Bice and Fenoglio, Ivana. “Toxic Potential of Mineral Dusts“. 21 October 2013. https://www.uvm.edu/~gdrusche/Classes/HCOL%20195/Elements%20article%20on%20toxicity%20of%20mineral%20dusts%202007.pdf
- Geology Page. “Top Radioactive Minerals“. 21 June 2017. https://www.geologypage.com/2017/06/top-radioactive-minerals.html
- Global Safety Management, Inc. “Safety Data Sheet: Hydrochloric Acid, ACS”. 8 January 2015. https://beta-static.fishersci.com/content/dam/fishersci/en_US/documents/programs/education/regulatory-documents/sds/chemicals/chemicals-h/S25358.pdf
- Merriam-Webster. “Toxicity”. 2022. https://www.merriam-webster.com/dictionary/toxicity
- Mindat. Numerous articles. 2022. https://www.mindat.org/
- Minerals Education Coalition. “Periodic Table of the Elements”. 2022. https://mineralseducationcoalition.org/mining-minerals-information/periodic-table-of-the-elements/
- National Library of Medicine. “ChemIDplus“. 2022. https://chem.nlm.nih.gov/chemidplus/chemidheavy.jsp
- National Park Service. “Conserve O Gram“. September 2006. https://www.nps.gov/museum/publications/conserveogram/11-10.pdf
- RDG. “An Overview of Minerals Toxicity“. 19 December 2020. https://www.academia.edu/40433628/An_Overview_of_Minerals_Toxicity
- Risk Assessment Information System. “Toxicity Profiles”. University of Tennessee. 2020. https://rais.ornl.gov/tools/tox_profiles.html
- Rock & Gem. “Hot Rocks: A Rockhound’s Guide to Radioactivity“. 24 July 2020. https://www.rockngem.com/hot-rocks-a-rockhounds-guide-to-radioactivity/#:~:text=Monazite%2C%20a%20rare%2Dearth%20phosphate,%2C%20beta%2C%20or%20gamma%20radiation
- Rocky. “The Top 11 Toxic Minerals – Lies the Internet Told You“. Where to Find Rocks. 5 August 2019. http://wheretofindrocks.com/the-top-11-toxic-minerals-lies-the-internet-told-you/
- Rowan, Alysson. “Here Be Dragons of The Care and Feeding of Radioactive Mineral Species“. 2008. http://randomseed.org/inheritance/wp-content/uploads/2013/12/article.RadioactiveMineralSpecimens.A4.pdf
- Schoonen, Martin AA and Roemer, Elizabeth J. “Mineral-Induced Formation of Reactive Oxygen Species”. December 2005. https://www.researchgate.net/publication/235936877_Mineral-Induced_Formation_of_Reactive_Oxygen_Species
- Tye, AM, Milodowski, AE, and Smedley, PL. “OR/17/001 The distribution of natural radioactivity in rocks”. Earthwise British Geological Survey. 2017. http://earthwise.bgs.ac.uk/index.php/OR/17/001_The_distribution_of_natural_radioactivity_in_rocks
- UAB Occupational Health and Safety. “Safe Handling, Storage, and Disposal of Hydrofluoric Acid User’s Guide”. 29 September 2016. https://www.uab.edu/ehs/images/docs/chem/HFUserGuide-2016-09-29.pdf
- United States Nuclear Regulatory Commission. “License-Exempt Consumer Products Uses of Radioactive Material“. 2 December 2020. https://www.nrc.gov/materials/miau/consumer-pdts.html
- U.S. Bureau of Mines. “Crystalline Silica Primer”. U.S. Department of the Interior. 1992. https://www.silica-safe.org/know-the-hazard/body/1-Crystalline-Silica-Primer.pdf
- Wikimedia Commons. Numerous images. 2022. https://commons.wikimedia.org/wiki/Category:Images
- Wikipedia. Numerous articles. 2022. https://en.wikipedia.org/wiki/Main_Page
Last Updated on 8 December 2023 by Angel Doran