GREEN PREHNITE WITH BLACK EPIDOTE FROM DJOUGA, KAYES REGION, MALI. ALTHOUGH PREHNITE IS NOT A ZEOLITE, IT IS FOUND IN BASALTIC ROCKS AND FORMS WITH SOME ZEOLITES (SEE OKENITE ON PREHNITE). IT IS A PHYLLOSILICATE OF CALCIUM AND ALUMINUM. THE CRYSTAL SYSTEM IS ORTHOMBIC, FORMING MAINLY IN GLOBULAR NODULES. HARDNESS IS 6-6.5. EPIDOTE IS ANOTHER CALCIUM-ALUMINUM COMPOUND. THE CRYSTALS ARE PRISMATIC WITH STRIATIONS AND ARE FIBROUS IN NATURE. HARDNESS IS 6-7. VERY NICE SPECIMENS FOR YOUR COLLECTION!