Can anyone explain why the Gem Society had Scolesite listed under the toxicity table as Hazard ( asbestos) when in fact it isn’t Asbestos? I was worried after reading the IGS table but am assured by a Geologist and another person in the field that it does not contain Asbestos.
That’s a good question. Based on some preliminary research, I’ve found that there is at least one member of the zeolite group (which contains natrolite, scolecite, and mesolite) that is a known carcinogen because of its fibrous structure, erionite. It’s “asbestos-like” but also sometimes classified as asbestos. The gemstones of the natrolite subgroup - natrolite, scolecite, mesolite - also have a fibrous structure, but I haven’t yet found sources stating they contain asbestos. The author of our toxicity table is also a geologist, however, I’ll have to do more review of the entries for natrolite, scolecite, and mesolite.
Pedro
IGS Admin
Thank You. I would appreciate it as it is quite confusing and for those of us with scolesite pieces in our collections this table makes it quite concerning too.
There’s good news and bad news about the gems in the natrolite subgroup.
Here’s the good news.
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The gemstones of the natrolite subgroup of zeolites (natrolite, scolecite, and mesolite) do not contain asbestos nor do they belong to the group of minerals classified as asbestos.
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To the best of my knowledge after researching available information, there are no known cases that indicate natrolite, scolecite, or mesolite pose health risks to people. If anyone is aware of studies that do show health risks associated with these minerals, please let IGS know.
I amended the entries for these three gemstones in the Gemstone Toxicity Table.
Here’s the bad news.
Erionite (like natrolite, scolecite, and mesolite) is a fibrous zeolite. To date, it’s the only fibrous zeolite known to be a carcinogen. Breathing airborne erionite fibers can cause mesothelioma. Like other fibrous zeolites, erionite doesn’t fall under the classification of asbestos. That doesn’t make it any less dangerous. In fact, “Erionite is the most carcinogenic mineral fiber documented in man and in rodent inhalation studies,” according to Ken Donaldson and Paul Borm, “Particle Toxicology” (2006), p. 20.
For this reason, I added notes to the toxicity table entries for natrolite, scolecite, and mesolite regarding erionite’s toxicity because researchers have cautioned that other fibrous zeolites could pose the same risk as erionite. However, to date, this has not been documented for these materials.
So, what’s the bottom line in terms of practical safety if you have some natrolites, scolecites, or mesolites as gemstones or mineral samples?
In cases in Turkey and North America where erionite has been linked to mesothelioma, exposure has occurred in locations where people lived or worked near erionite-rich rocks and were exposed to dust from this material over extended periods of time.
If you are cutting or faceting natrolites, scolecites, or mesolites, please take precautions against inhaling dust particles, such as wearing a dust mask or using a glovebox. See our article on lapidary safety for more information. Of course, taking precautions against inhaling dust particles is a standard safety measure when cutting or faceting any gemstones.
If you have natrolite, scolecite, or mesolite in a gemstone or mineral collection, it’s important to keep the scale of exposure in mind. I think it’s safe to say that normal handling or occasional wearing of these stones should pose no health risks. However, note that these zeolites have a hardness of 5. Household dust, with a hardness of 7, will gradually scratch any exposed zeolites, which could release airborne fibers. It would be prudent to keep such pieces in storage or on display in closed cases out of an abundance of caution.
Pedro
IGS Admin
Thank You so much for this information. It has been most helpful albeit still a little concerning.