Cronstedtite is an uncommon iron silicate mineral that has a most unusual growth habit. If you look carefully, you can see that the elliptical Cronstedtite aggregate consists of flat-topped, conical crystals with a roughly hexagonal outline exhibiting a satin to bright luster. These black Cronstedtite crystals, from 1 to 3 mm in size rise off the brown-orange, granular Siderite matrix by about 3 mm, all on a matrix composed of fractured Quartz. A good, and unusual, combination piece from the famous Salsigne Mine in France.