Spessartite


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Related to Spessartite: grossularite

spessartite

[′spes·ər‚tīt]
(mineralogy)
Mn3 Al2(SiO4)3 A mineral composed of manganese aluminum silicate with small amounts of iron, magnesium, or other elements.
(petrology)
A lamprophyre composed of a sodic plagioclase groundmass in which green hornblende phenocrysts are embedded; also contains accessory olivine, biotite, apatite, and opaque oxides.

Spessartite

 

a melanocratic veinstone consisting of medium plagioclase (andesine), hornblende, or monoclinic pyroxene (diopside-augite). Apatite, iron minerals, and, frequently, zircon are present as secondary minerals.

Spessartite is a fine-grained and uniform rock, although individual large crystals (porphyritic impregnations), indicating crystallization in several stages, are sometimes encountered. Spessartite belongs to the lamprophyre group. It is formed in the final stages of crystallization of intrusive granitic mountain masses of low depth and, apparently, is the product of crystallization of a relatively low-temperature, water-rich magma.

References in periodicals archive ?
Nigeria has, over the years, intermittently produced some of the world's most impressive gemstones, more particularly rubellite tourmaline, aquamarine, spessartite garnet, morganite, goshenite, along with sapphire, amethyst and white, blue, and yellow topaz.
However, the Umbalites have a very special feature which is of having a hint of Spessartite garnet component in them which them one of the rarest garnets of all kind.
Diorella ring in yellow gold with amethyst, Diamonds, and spessartite garnets, CHRISTIAN DIOR.
Shangbao Hunan calcite, bismuthinite, dolomite, fluorite, pyrite, quartz Shangyangpo Hubei turquoise Shilu Guangdong azurite, malachite Shilu Hainan hematite Shimen Hunan calcite, orpiment, picropharmacolite, (Jiepiayu) realgar Shitouzui Hubei azurite Shizhuyuan Hunan bismuthinite, calcite, cassiterite, fluorite, galena, muscovite, pyrrhotite, pyrite, scheelite, sphalerite, Ta/Nb oxides, wolframite Shuijingping Fujian feldspar, fluorite, helvite, pyrite, smoky quartz, spessartite Shuikoushan see Kangjiawan Siding Guangxi, hydrozincite Zhuang A.