Black tourmaline from Brazil
Weight-
5g-15g
Sizes-
Various
You will be picked one at random.
Black tourmaline is commonly known as schorl.
Crystal system- Trigonal (forming elongated prismatic crystals,often with a triangular cross-section and vertical striations)
Mineral class- Cyclosilicate (ring silicate) belonging to the tourmaline group.
Rock formation- Igneous and metamorphic environments,mist commonly found in slow-cooling pegmatites,granite,hydrothermal veins,and acid deep gangue rocks from boron-rich magmatic fluids.
Hardness- 7-7.5 on the MOHs scale.
