Fossil Clam Shell w/Vivianite, Russia F1705 - Fossil Clam Shell w/Vivianite. Russia. Is is a mineral specimen or fossil specimen. Yes! Both! Fossilized clam shells nearly completely filled with Vivianite. Hydrous phosphate of iron. Hardness 1-1/2 to 2. Monoclinic crystals, usually in short to long prismatic crystals. Dark blue crystals. Vivianite is found as a minor constituent in several environments, including sedimentary rocks, vein deposits and pegmatites, but its principal occurance is in the disseminated hydrothermal replacement deposits. Thus explain the material forming in clam shells. From Russia.! GREAT PRICE $12.50  (You can always remove items from your cart later if you wish)