Cordierite

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cordierite

[′kȯrd·ē·ə‚rīt]
(mineralogy)
Mg2(Al4Si5O18) A blue, orthorhombic magnesium aluminosilicate mineral frequently occurring associated with thermally metamorphosed rocks derived from argillaceous sediments.

Cordierite

 

[named for French geologist P. Cordier (1777–1861)], also iolite or dichroite, a mineral, a complex aluminosilicate of aluminum, magnesium, and iron; chemical composition, (Mg, Fe)2Al3[AlSi5O18]. Its crystal structure is characterized by a ring construction similar to that of beryllium. Cordierite crystallizes in the orthorhombic system. It occurs in the form of prismatic crystals, irregular clusters, and grains of blue-gray, blue, violet, or brown color; sometimes it is colorless. It has a hardness of 7.0–7.5 on the mineralogical scale and a density of 2,600–2,660 kg/m3. Dichroism is a characteristic feature and is highly pronounced in transparent grains. The mineral effloresces easily to form talc, mica, and other secondary minerals. Cordierite is formed during contact metamorphosis of rocks rich in aluminum and magnesium. Transparent varieties of cordierite are used as gems.

References in periodicals archive ?
In addition to tracking direction, IOLITE also assists swimmers with information on distance, speed and cadence.
We look forward very much to working closely with Maurice Klaus in the coming years to develop Iolite.
Recommended exploration includes bulk sampling of the star-sapphire, iolite and garnet occurrences while sourcing gemstone recovery methods to determine the most effective method of gem extraction from the mineralized rock.
A budget has been set by Hampton Court and Anglo Swiss for $300,000 for continued exploration, bulk sampling of the star-sapphire, iolite and garnet occurrences and sourcing gemstone recovery methods to determine the most effective method of gem extraction from the mineralized rock.
The Blu Starr Gemstone property to-date has yielded numerous precious and semi-precious gemstones including star-sapphire, iolite, garnet, aquamarine, beryl, tourmaline, titanite, moonstone and several varieties of smoky, rose and star quartz.
The new sapphire and iolite outcrops have expanded the breadth of the known gemstone occurrences and the new garnet showings outcrop in a previously unexplored area.
The Company wishes to emphasize that, although the Blu Starr property has demonstrated the potential to host gem-quality sapphire, iolite and garnet, the property is at an early stage of evaluation and considerable studies of the mineralized areas and the production and recovery process remain to be completed.
The Gemological Institute of America (the official nonprofit educational organization for the jewelry industry), in their "Gems & Gemology," addressed the significance of Anglo's iolite, garnet, star-sapphire, etc.
Gemstones discovered to-date include numerous showings containing star sapphire, iolite, garnet, aquamarine, titanite, moonstone and several varieties of quartz crystals plus a recent discovery of a large mineralized area containing showings of crystalined graphite.
One stunning set of earrings features a pair of brilliant cut iolite gemstones (total weight = 4.
include amethysts, aquamarines, garnets, iolites, opals, peridots, spinels, tanzanites, topaz, and tourmalines.