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Chemical formulaNa4(CaCeFeMn)2ZrSi6O17(OHCl)2
ColorRed, magenta, brown; also blue and yellow
Crystal habitGranular, tabular
Crystal systemTrigonal
Cleavage[0001] Imperfect
Mohs Scale hardness5 - 5.5
Refractive index1.598 - 1.602
PleochroismWeak, brown-red to red-pink to yellow
Specific gravity2.8 - 3
DiaphaneityTransparent to translucent
Other Characteristics Mildly Radioactive

Eudialyte, whose name derives from the Greek eu and dialytos, meaning "welthruloosa", is a somewhat rare, red silicate mineral, which forms in alkaline igneous rocks, such as nepheline syenites. Its name alludes to its ready solubility in acid.


Uses of eudialyte

Eudialyte is used as a minor ore of zirconium. Another use of eudialyte is as a minor gemstone, but this use is limited by its rarity, which is compounded by its poor crystal habit. These factors make eudialyte of primary interest as a collector's mineral.

Associated minerals

Eudialyte is found associated with other alkalic igneous minerals, in addition to the some minerals common to most igneous material in general. These minerals include:

Alternative names

Alternative names of eudialyte include: almandine spar and eudalite. Eucolite is the name of an altered form.

Notes for identification

Eudialyte's rarity makes locality useful in its identification. Prominent localities of eudialyte include Mont Saint-Hilaire in Canada and the Kola Peninsula in Russia, but it is also found in Greenland, Norway, and Arkansas. The lack of crystal habit, associated with color, is also useful for identification, as are associated minerals. A pink-red mineral with no good crystals associated with other alkaline igneous material, especially nepheline and aegirine, is a good indication a specimen is eudialyte.


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This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Eudialyte". A list of authors is available in Wikipedia.
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