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These chess pieces have laid undisturbed for a long time (15-20 years?). In this time, they seem to have grown clear/white, spiny, long crystals. I'm wondering if they are dangerous, but also curious to know what type of mineral both the chess pieces, and the spines, are made from.

enter image description here

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    $\begingroup$ Some more information is probably needed. What is the composition of the pieces? How have they been stored (humidity, temperature)? and finally where in the world has this happened? $\endgroup$ – Peter Jansson Jun 10 '18 at 12:59
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    $\begingroup$ It looks like your chess pieces may have been carved from asbestos, they are not growing fibers they are made of it and as they wear out they fray and protrude. $\endgroup$ – John Jun 10 '18 at 13:47
  • $\begingroup$ What is the location did you found them ? $\endgroup$ – PROBERT Jun 10 '18 at 14:58
  • $\begingroup$ @John I doubt that this is asbestos. The crystals are perfectly straight in some cases. If this was fraying asbestos, they would be curved. Also, if this was the case I'd expect the chess pieces to be completely covered by fibres, and you can clearly see that the material it's made from isn't actually fibrous. So where are the alleged asbestos fibres fraying from? I suspect this could be some sort of hydrated carbonate (sodium, potassium, magnesium) crystallising upon reaction of moisture with any carbonates in the rock the pieces are made from. $\endgroup$ – Gimelist Jun 11 '18 at 11:48
  • $\begingroup$ Some tests that you can do: First of all, be gentle and use gloves just in case this is indeed asbestos of some other hazardous material (I doubt that it is). Try to take some with tweezers. Do they snap? Do they bend? If they bend, do they return to the original shape once you leave them? Place some fibres on a glass slide/plate/whatever. Put a few drops of water on them. Wait a few minutes. Do they dissolve or disintegrate? Try adding white vinegar on fresh fibres. Do they fizz? Do you some any bubbles coming out? $\endgroup$ – Gimelist Jun 11 '18 at 11:51
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Here's an answer from a curator in a mineralogy museum:

I'd go for soluble Ca salt eg acetate formed by reaction of limestone chess pieces with organic acids in nearby materials?

And:

Growths like this are quite common in museum specimens. The Ca acetate mineral calclacite was first discovered in this way: https://www.mindat.org/min-862.html

And:

Unseasoned oak furniture is blamed for this kind of thing.🌳🗄️


I'll add that it does seem like limestone. I think I can even identify fossil-looking things, particularly in the top chess piece.

Even though at first look it might seem like asbestos, it's not. Refer to the comments on the original question for my opinion why.

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