Is a Calcium Iron Magnesium Carbonate with formula Ca(Fe, Mg, Mn)(CO3)2, and hardness of 3.5-4. Ankerite ,dolomite and siderite are often confused with each other,Ankerite however is usually more dense, opaque and deeply colored than dolomite; but not as much as siderite. Never transparent,often traslucent or opaque.
This material comes from Arbaz, Aosta, Valley, Italy.
Size: 9.5x7x4.7 mm.