Top Results for Feldspar

Sunstone is a plagioclase feldspar mineral recognized for its distinctive aventurescence, an optical effect that creates a glittery appearance. This phenomenon is caused by flat, reflective inclusions of hematite, goethite, or copper within the stone. Gem-quality sunstone, particularly copper-bearin...

Spectrolite is a trade name for a variety of labradorite feldspar found exclusively in Finland, particularly in the Ylämaa region. It is distinguished from other labradorite by its labradorescence, exhibiting a vivid, full spectrum of colors including blues, greens, yellows, and occasionally reds an...

Labradorite is a calcium-rich plagioclase feldspar mineral valued for labradorescence, an optical effect in which internal reflections produce shifting blue, green, yellow, or other colors as the stone moves relative to light. It occurs in igneous rocks such as anorthosite and is used as an ornament...

Spectrolite is a trade name commonly used for a dark, strongly iridescent variety of labradorite feldspar associated with Finland. Its polished surfaces can display vivid blue, green, yellow, orange, and violet flashes caused by the feldspar's internal optical structure, a phenomenon known as labrad...

Andesine is a plagioclase feldspar mineral with a composition intermediate between albite and anorthite. It is named after the Andes Mountains, where rocks containing the mineral are widespread. Andesine commonly occurs in volcanic and metamorphic rocks and may appear white, gray, yellow, green, or...

Sunstone is a variety of plagioclase feldspar known for aventurescence, a glittering optical effect produced when light reflects from tiny inclusions inside the mineral. The inclusions can include copper or hematite and may create reddish, orange, or golden flashes when the stone is viewed from part...

Orthoclase is a potassium-rich tectosilicate feldspar with the ideal formula KAlSi3O8 and a monoclinic crystal structure. It is a common rock-forming mineral in igneous rocks and also occurs in some metamorphic and sedimentary settings. Transparent yellow to champagne orthoclase may be faceted as a...

Bytownite is a calcium-rich member of the plagioclase feldspar solid-solution series, with composition between labradorite and anorthite. The name was introduced in the nineteenth century for material found near Bytown, the former name of Ottawa, Canada; the original occurrence was later understood...

Sanidine is the high-temperature form of potassium feldspar, with a composition close to KAlSi3O8 and a monoclinic crystal structure. It is commonly found in potassium-rich volcanic rocks such as rhyolite and other rocks that crystallized or equilibrated at high temperature; its rapid cooling can pr...

Andesine-labradorite is a trade name used for gem-quality plagioclase feldspar material whose composition and appearance fall near the andesine-labradorite range. Specimens may show red, orange, green, or multicolored body colors and feldspar aventurescence or labradorescence, but the identity and o...

Amazonite is the blue-green variety of microcline, a potassium feldspar. It is typically opaque to translucent, with color ranging from pale green to blue-green and often with white streaks or patches. Documented localities include Colorado and Virginia in the United States, as well as Russia, Madag...