Sunstone Value, Price, and Jewelry Information

Sunstone, Variety of Oligoclase from India By Ra'ike (Own work) [GFDL or CC-BY-SA-3.0], via Wikimedia Commons

Sunstone

Sunstone Value

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

Sunstone Value via Gem Price Guide

Accompanying value information:
Not found
Red, Green & Bicolored .10 to .99 carats 1 to 100 carats
SI to clean to /ct to /ct
Peach .5 to 20 carats
SI to clean to /ct.
Schiller 1 carat plus
SI to clean to /ct
Yellow 1 carat plus
SI to clean to /ct
Cabochons All sizes
Red to /ct
Schiller to /ct

Sunstone Information

Data Value
Name Sunstone
Is a Variety of Feldspar
Crystallography Triclinic.
Refractive Index 1.537-1.550
Colors Red, green, yellow, and peach body colors.
Hardness 6-6.5
Wearability Poor
Fracture Conchoidal, uneven, splintery
Birefringence 0.007-0.011
Cleavage Perfect two directions
Absorption Spectrum Not diagnostic.
Identifying Characteristics reddish or golden platelets with metallic luster
Pleochroism None.
Optics Biaxial (-). 2V = 82°.
Optic Sign Biaxial -
Luster Vitreous.
Specific Gravity 2.62-2.67
Transparency Transparent.
Phenomena Aventurescence, schiller.

Comments

This material contains hematite or goethite inclusions, which reflect light in parallel orientation and create a sparkling sheen in gold to brown color shades. Sunstone may be oligoclase or labradorite in composition and is much admired as a cabochon material among hobbyists. (Labradorite with aventurescence caused by copper inclusions is known as Oregon sunstone and is described in a separate gem listing). Very fine material is not abundant and is hard to obtain.

Occurrence

  • New Mexico; New York; North Carolina: Maine; Pennsylvania; Virginia.
  • Lake Baikal, USSR; Bancroft area, Ontario, Canada.
  • Tvedestrand and Hitterö, Norway; as masses in quartz veins.
  • Lake Huron (Canada side): brownish to pink color.
  • Kangayam, India.
  • Harts Range, N. T. Australia: an untwinned microcline microperthite with aventurine-type reflections due to inclusions of thin, brownish-red hexagonal inclusions, in two sets at 90° angles. Properties are: a= 1.520; β= 1.525; γ= 1.527; birefringence = 0.007; S.G. = 2.57; hardness = 6-6.5; no UV fluorescence.

Stone Sizes

Cabochons from Norwegian and Indian material may reach 100 carats or more. Most available material cuts smaller stones, however. This is because the rough is usually badly shattered and cracked.

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