The d4 is a special kind of petrified wood. The numbered d6 is (sintered) turquoise. The d8 is a cats eye. The blue d10 is lapis lazuli. The red d10 (tens) is red sandstone with gold flecks. The d12 is opal. The d20 is malachite. The funky d12 with astrological symbols is blue sandstone with gold fleck. The really funky d6 (a Tibetan "Mo" divination die) is yellow jade.
IIRC, tigers eye isn't a naturally occurring stone, and is in fact the byproduct of converting asbestos to a non-carcinogenic product. The different colors of this "gemstone" are achieved with different temperatures during said process.
Regardless, fun stuff! ๐คฉ๐ค๐ผ
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Oh, sweet! TIL ๐ค๐ผ
Chrysoberyl is the naturally-occurring "cat's eye" gem, though scapolite, spinel, tourmaline, corundum, and even quartz can display this behaviour as well.
There are probably artificial cat's eye gems that are made that way, but natural cat's eye is a thing.
Oh, my. Say more words. ๐ฅน๐
Ironic, I just noticed my typo. ๐คฆ๐ผโโ๏ธ