Phlogopite Mica,black Tourmaline,halite And Orthoclase

Phlogopite Mica,black Tourmaline,halite And Orthoclase from Erongo Mountain Erongo region Namibia Size- 5.3cm x 5.6cm x 2.6cm Weight- 76g You will receive the item in the photo Phlogopite mica: Crystal system- Monoclinic. It typically forms thick tabular crystals,pseudo-hexagonal prisms,or large sheets known as books. Mineral class- Silicates (specifically a phyllosilicates or sheet silicate belonging to the mica group. Rock formation- it commonly forms via contact metamorphism in magnesium- rich environments,such as metamorphosed dolomitic limestones and marbles.it also occurs as a primary magmatic mineral in silica poor,ultramafic igneous rocks like kimberlites and lamproites. Hardness-2.5-3 on the MOHs scale Black tourmaline: Crystal system-Trigonal. It forms elongated prismatic crystals that characteristically feature heavy vertical growth striations and a rounded triangular cross-section. Mineral class- silicates Rock formation- most commonly crystallizes in igneous granitic pegmatites from boron- rich hydrothermal fluids. It can also form in high-grade metamorphic rocks like schists and gneisses. Hardness-7-7.5 on the MOHs scale Halite: Crystal system- Isometric. Mineral class- halides Rock formation- formed strictly in sedimentary environments. It precipitates out of solution as an evaporite deposits when landlocked seas,saline lakes,or salt flats dry up. Hardness-2-2.5 on the MOHs scale Orthoclase: Crystal system-monoclinic. It often grows as prismatic or tabular crystals and regularly exhibits Carlsbad twinning, Mineral class-silicates Rock formation - primarily forms during the slow cooling of silica-rich intrusive igneous rocks like carnitas,syenites and pegmatites.it also commonly develops in high grade metamorphic rocks like gneiss. Hardness- 6 on the MOHs scale