Natural Cobalt Spinel
Cut: Mixed Cut
Weight : 3.12 Cts
Colour: Deep Violetish Green Blue
Dimension : 9.31 mm x 7.18 mm x 5.48 mm
Species: Natural Spinel
Variety: Cobalt Spinel
“GGTL” Certified (GIA Alumni Association Member)
Spinel is the magnesium-aluminum member of the larger spinel group of minerals with chemical formula MgAl₂O₄. Spinel is actually a large group of minerals. Gahnite, hercynite, ceylonite, picotite, and galaxite are all part of the spinel group.
This oxide mineral is a Cubic crystal system with 7.5–8.0 hardness according to the Mohs hardness scale. Spinels Specific Gravity is depending on the composition of chemicals such as Zn-rich spinel can be as high as 4.40, otherwise, it averages from 3.58 to 3.61. Spinel has many colors such as red, pink, blue, lavender/violet, dark green, brown, black, colorless, gray. Spinel is a single reflective Non-pleochroic gemstone and Anomalous in some blue zincian varieties. It can be found as Opaque, Translucent or transparent. Spinel RI value is n = 1.719
Some red and pink spinels have fluorescence under UV Light. also, Some spinels have magnetism Weak to medium. Natural spinels typically are not enhanced. Spinels are found in Madagascar, Sri Lanka, Vietnam, Myanmar, Tanzania, Kenya, Nigeria, Afghanistan, Albania, Algeria, Atlantic Ocean, Australia, Belgium, Bolivia, Brazil, Cambodia, Canada. Spinel has long been found in the gemstone-bearing gravel of Sri Lanka. Since 2000 in several locations around the world have been discovered spinels with unusual vivid colors.
when the mineral is pure, it’s colorless. That’s called allochromatic gemstones. Als, Spinels are found with 4-rayed stars and 6-rayed stars. Some spinels are found with a color-changing effect such as Blue to violet, Grayish-blue to reddish-violet and some stones from Sri Lanka change from violet to reddish violet, due to the presence of Fe, Cr, and V. Blue Spinel is a very special gemstone because it is one of the few that occur naturally. The blue Spinel is colored from the impurity of Cobalt in the crystal lattice. High Color saturation in blue Spinels are always colored by Cobalt and are extremely rare to find. Cobalt spinel has high market value.