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.

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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
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    $\begingroup$ @Gimelist not all of the asbestos group mineral have uniform crystals some can also form as a mass of smaller "crystals" and of course industrially formed asbestos does not look fibrous without a microscope, and of course asbestos can occur as an inclusion in other minerals. It could even be fiberglass which would not look fibrous due to the resin. I do agree some more effort into identifying the fiber composition could go a long way to making this easier.I am curious as to what makes you think the fibere would be curved in asbestos. $\endgroup$ – John Jun 11 '18 at 14:23
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    $\begingroup$ @John in my opinion, this is definitely a recrystallisation. I’ll perform some further tests as suggested and report back. $\endgroup$ – joshginges Jun 12 '18 at 12:41

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?


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


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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