At the beginning of last week I posted the above picture of Realgar and Native Arsenic on my Facebook page with the caption "Toxic red stuff for Monday".
Beautiful red crystals of realgar against a black and white background do look great in detail.
My strapline did provoke some interesting discussion and points of view about minerals and toxicity, with some strong feelings.
Dr Andrew Christy (Andychristyite) was quick to mention or suggest routhierite, "redder and even more toxic, with a bit of thallium and mercury"
Absolutely, a combination of some pretty nasty elements, but how toxic really?
Another comment from Jan Hurr raised this question and further asked if there were any LD50 values for these minerals?
|Lethal Dosage (LD50) Values. An LD50 is a standard measurement of acute toxicity that is stated in milligrams (mg) of pesticide per kilogram (kg) of body weight. AnLD50 represents the individual dose required to kill 50 percent of a population of test animals (e.g., rats, fish, mice, cockroaches).
I beliveve the answer to this is No, however some of the synthetic or refined mineral products will have LD50 values.
Jan went on to give the very good advice that you should not eat these minerals and always wash your hands after handling any mineral.
And indeed minerals like realgar and routhierite although containing toxic heavy metal elements, these are bound together and tend not to be active in their natural state.
The discusion then turned to minerals that really are dangerous due to the ability to dissolve or pass through the skin, one serious contender being arsenolite or claudetite.
The discussion told us the as little as 50mg could be deadly and due to its association with other minerals skutterudite might not be recognised as such.
Jan did make a very good point about misinformation and mineral dangers - an example being on listverse where galena is cited as 7th most toxic mineral.
I would say that such information should be taken with a pinch of salt but that is not very good advice either!