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

The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.

Eudialyte Information

DataValue
NameEudialyte
Crystallography Hexagonal (trigonal); tabular crystals, may be hexagonal or trigonal; also prismatic, rhombohedral, massive.
Colors Shades of brownish red, yellowish brown, pink, red. Often translucent.
Luster Vitreous; greasy; may be dull.
Fracture Uneven; brittle.
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.
Spectral Not diagnostic.
FormulaNa4( Ca,Fe,Ce,Mn)2ZrSi6O17(OH,CI)2 (Note: Eucolite= calcium-rich variety)
Pleochroism Varies with body color.

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.