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www.mineralgallery.co.za Minerals A-E |
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Name
Aegirine
Chemistry
NaFeSi2O6 , Sodium Iron Silicate
Uses
As a mineral specimen
Color
Black to greenish black.
Hardness
6.2 -6.8
Specific gravity
3.4-3.5
Crystals
(monoclinic) columnar,acicular, tabular,vertically striped; usually intergrowth; often twinning.
Accompanied by:
Feldspars, nepheline and yellow zircon crystals.
Similar to:
Hornblende, arfvedsonite and actinolite.
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Aegirine is a favorite amongst mineral collectors. It contrast beautifully with the orthoclase feldspar on which it is found in our specimens. It forms long needlelike crystals which oftentimes have a pyramidal finish on the edges. The luster is vitreous.
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The crystals are opaque black or green. The samples from Zomba mountain in Malawi have become world renown for their beauty.
Gerdus often goes up to Malawi. The crystals are collected from cracks and crevices in the bare granite. The locals digs it out with primitive tools. They sometimes have to go down a bare rock-like with ropes for 6-10 meters to get to the pockets.
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It belongs to the pyroxene group.The pyroxenes are an important group of rock-forming silicate minerals that are characterized by a specific arrangement of atoms and similar physical, optical, and chemical properties.
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They occur as both major and minor constituents in a wide variety of igneous, metamorphic, and sedimentary rocks, and are common in lunar rocks and stony meteorites.
The crystals are generally prismatic with a square cross-section, but most pyroxenes usually occur as irregular grains. The exceptions to this are aegirine, which often occurs as long, needlelike crystals, and spodumene, which can occur as giant crystals up to 3 m (10 ft) thick and more than 15 m (50 ft) long.
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Aegerine is generally found in alkaline igneous rocks, such as syenites and alkali granites.
