Uuvarovite, a form of garnet
Source: Wikipedia
Des Esseintes decorates his tortoise in Huysmans's Au Rebours [Against Nature]:
"This is how he composed his bouquet of flowers: the leaves were set with jewels of a pronounced, distinct green; the chrysoberyls of asparagus green; the chrysolites of leek green; the olivines of olive green. They hung from branches of almandine and ouwarovite of a violet red, darting spangles of a hard brilliance like tartar micas gleaming through forest depths."