Well formed glossy terminated Ilvaite Crystals. Not common and these are very good form from the private collection. Mounted on a perspex pad for enhanced display. Now for sale at a bargain price. My pics don’t show how black the Crystals are.
3cm x 3.3cm x 4.8cm, 62g.
Huanggang Mine, Ulanhad, Chifeng, Inner Mongolia.
Calcium Iron Silicate Hydroxide: CaFe3OSi2O7(OH).
Ilvaite is not a common mineral in rock shops. Its crystals are usually not all that attractive, but some specimens are real standouts with well-formed crystals with a shiny black color and an opaque submetallic luster. Its diamond-shaped crystals with wedge-like terminations can form very interesting specimens. Ilvaite is a member of the Sorosilicate subclass of the silicate minerals. Sorosilicates have an unusual basic unit of Si2O7. This group of atoms is composed of two silicate tetrahedrons that share one oxygen giving the group an hourglass shape. A fine specimen of Ilvaite can be a valuable addition to any collection.