Packaging unit with 0.5 kg; these are approx. 17 - 22 tumbled prehnites.
In size XL (extra large), the Tumbled Stones are 2.8 - 3.3 cm in size.
The mineral prehnite was named after Colonel Hendrik von Prehn (1733 - 1785); spellings such as phrenite, prenhite, prenith or phrenite are therefore incorrect. Von Prehn brought back samples from the Cape of Good Hope in 1783 and had them examined by the mineralogist Abraham Gottlob Werner. He described the material and named it prehnite after von Prehn. The stone is the first mineral to be named after a person.
Trade names for Prehnt are cape chrysolite and cape emerald, earlier common names are aedelite, chiltonite, coupholite and edelite.
Place of discovery: Bafoulabé, Kayes region (southwest Mali)