The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.
|Is a Variety of||Feldspar|
|Identifying Characteristics||Reddish or golden platelets with metallic luster|
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. Very fine material is not abundant and is hard to obtain.
- 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.
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.