Feldspar
Image: Robert M. Lavinsky (CC BY-SA 3.0)
Mineral NameFeldspar
Chemical Formula(K,Na,Ca)(Al,Si)4O8
Mohs Hardness6
Crystal Systemcubic
Lustervitreous
Streak Colorwhite
CleavagePerfect in two directions, nearly at 90 degrees
Fractureuneven to conchoidal
Specific Gravity2.55
Colorswhite, pink, gray, green, yellow, brown
Transparencytranslucent
Type LocalityErongo Mountain, Usakos and Omaruru Districts, Erongo Region, Namibia
Mineral GroupSilicates (Tectosilicates, Feldspar Group)
Usesceramics, glass manufacturing, abrasives, gemstones, building materials
Associated Mineralsschorl, quartz, mica, amphibole, pyroxene
Raritycommon
Description
The image displays a large, blocky, white to off-white feldspar crystal, exhibiting characteristic cleavage planes, associated with a prominent black schorl tourmaline crystal.
Geological Context
Feldspars are the most abundant group of minerals in the Earth's crust, forming essential components of igneous, metamorphic, and many sedimentary rocks. They crystallize from magma and lava or are formed during regional metamorphism.
