The dual parallel growth terminations on this one are excellent. Actually there is a third small one at the front, between the two. Stands up perfectly for display in a couple of different ways. Excellent specimen!
Out of mineralogical interest, there is actually a small broken end of another crystal around the back of the piece and what is unique about it is that it was formed in a perpendicular, angled direction to the main crystal. None of the rest that I acquired exhibited anything other than parallel growth – nor do I remember others from the original lot evidencing any intergrowth like that.
About These Dravite Tourmalines
These dravite tourmalines from Serra Branca, Brazil, are sharp crystals!
All of the crystals are doubly-terminated. The prism faces have a bright lustre, like black opaque glass. Under bright lights (such as the photography lighting), a few subsurface glints of internal brown are visible in some, but under normal lighting, to the eye the crystals look essentially black and opaque. The termination faces vary, with many showing a slightly silky lustre and delicate texture. Most of these are crisp, simple crystals (they really look like idealized crystal models!) and some have a bit more complexity to them. None of these crystals are perfect all-around – they have a little edge wear or minor nicking in some place or another – however, these are high quality specimens and they are the best of the lot.
These specimens were collected in the 1990s and they were squirrelled away in Brazil. Frank Melanson had analysis done to confirm that they should be labeled dravite.