ETTRINGITE
Specimen ett-4
$ 50.00Dims: 5.6x1.2x0.9" (14.2x3.0x2.2 cm)
Wt: 3.9 oz. (109.6g)
N'Chwaning Mine, South Africa
This is a really interesting specimen. Its core is filled with thin black blades of some mineral with a vitreous luster (looks a bit like schorl). These crystals also form a dusting on the outer surface. The bulk of the specimen is a radiating mass of crystals (pale brown, opaque, a soft woody feel) which looks like a wooden stick, but I believe is a mineral of some type. Over this is a crust of small, light brown bruceite crystals. These are translucent to dimly transparent and have a pearly luster. And on this cylinder (perhaps it was a stalactite) are several crystals of ettringite. While most of the ettringite is colorless or white, the outer layer (where it still remains) is a vibrant yellow. There is a scattering of very small bright yellow ettringite crystals scattered over the specimen. This specimen has been repaired - the stalactite appears to have broken into 4 pieces which were glued back together.