Eudialyte Value, Price, and Jewelry Information


Eudialyte
Rob Lavinsky, iRocks.com – CC-BY-SA-3.0 [CC-BY-SA-3.0], via Wikimedia Commons

Although cabochons could be cut from massive eudialite or translucent crystals, transparent material suitable for faceting is elusive and always small.

Eudialyte Value

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Eudialyte Information

DataValue
NameEudialyte
Crystallography Hexagonal (trigonal); tabular crystals, may be hexagonal or trigonal; also prismatic, rhombohedral, massive.
Refractive Index 1.591-1.633
Colors Shades of brownish red, yellowish brown, pink, red.
Luster Vitreous; greasy; may be dull.
Fracture Uneven
Hardness 5 - 5.5
Specific Gravity 2.74-2.98
Birefringence 0.003-0.010
Cleavage Basal, indistinct
Stone SizesFaceted gems well under 1 carat in size have been cut from Quebec material. These are deep red and extremely rare. National Museums of Canada (Ottawa, Ontario): 0.30, 0.40 (intense red, Sheffield Lake, Quebec, Canada).
Luminescence Not reported.
Transparency Often translucent, rarely transparent.
Absorption Spectrum Not diagnostic.
FormulaNa4( Ca,Fe,Ce,Mn)2ZrSi6O17(OH,CI)2 (Note: Eucolite= calcium-rich variety)
Pleochroism Varies with body color.
Optics = 1.591-1.623; = 1.594-1.633. Uniaxial (+) but sign variable (eucolite reported to be (-) with higher indices and SG).

Opticso= 1.591-1.623; e= 1.594-1.633.

Uniaxial (+) but sign variable (eucolite reported to be (-) with higher indices and S.G.).

Occurrence: Nepheline syenites and associated pegmatites:

Julienhaab District. Greenland: crystals up to I inch in length.

Kola Peninsula, USSR: Pilansberg. South Africa. Ampasibitika, Madagascar

Magnet Cove, Arkansas: rich red color, in feldspar.

Mt. Ste. Hilaire, Quebec, Canada: facetable (o = 1.596; e = 1.600; birefringence = 0.004).

Kipawa Complex. Sheffield Lake, Temiscamingue County,Quebec, Canada: red, facetable.

Sweden: o = 1.598; e = 1.604; Birefringence = 0.004; S.G. = 2.88.

Comments: Although cabochons could be cut from massive eudialite or translucent crystals, transparent material suitable for faceting is elusive and always small.

Name: From Greek words meaning easy to dissolve because of its easy solubility in acids.