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
