Gold/Golden Sheen Sapphire
General
Category	Oxide mineral
Formula	Aluminium oxide, Al 2 O 3
Crystal system	Trigonal
Crystal class	Hexagonal scalenohedral (3m) H-M symbol: (32/m)
Space group	R3c
Identification
Color	Typically metallic gold, copper or bronze, blue, green but varies
Crystal habit	As crystals, massive and granular
Fracture	Conchoidal, splintery
Mohs scale hardness	9.0
Luster	Vitreous
Specific gravity	3.95–4.03
Optical properties	Abbe number 72.2
Refractive index	nω=1.768–1.772 nε=1.760–1.763, Birefringence 0.008
Pleochroism	Strong
Melting point	2,030–2,050 °C
Fusibility	Infusible
Solubility	Insoluble
Other characteristics	Coefficient of thermal expansion (5.0–6.6)×10−6/K relative permittivity at 20 °C ε = 8.9–11.1 (anisotropic). [1]

Golden sheen sapphire, (or goldsheen sapphire) is a recently discovered variety of corundum. ^[2] Goldsheen sapphire has been tested and confirmed in lab reports as "natural sapphire" by GIA, GIT, GRS, AIGS, Tokio gem labs and Lotus.

Contents

• Evidence
• Source
• References

Goldsheen sapphire has a golden shine, almost like gold. Translucent blue, green or yellow material is sometimes present together with the gold. ^{[3] [2]} Particularly prominent is hematite which will often result in the formation of geometric hexagonal patterns within the gemstone crystal. ^[4]

Evidence

Several articles, including the Journal of Gemmology state that gold sheen sapphire is high in iron and titanium oxide. ^[2] It has inclusions of ilmenite, hematite (gold color) ^[5] and magnetite (black). It exhibits asterism and hexagonal growth, ^[6] a lack of UV fluorescence, healed fractures and polysynthetic twinning (parallel lines). Golden sheen has a stronger golden shine and sometimes has blue and gold in the same stone. ^[2]

Source

Previously, it was claimed in the Journal of Gemmology (JoG), ^[2] that the source is a depleted mine in Kenya close to the border of Somalia. TJN Colors, GIT and In Color ^{[7] [8] [9]} also previously published that the origin was Kenya. However, GIA Tokyo ^[10] and Gems and Jewellery ^[6] stated in 2018 that the location is not known. GIA ^[10] and JoG stated that golden sheen sapphires are reportedly mined in northeastern Kenya, there is no other published chemical data available from this region ^[10]

References