Spinel Vs Sapphire Hardness

However hundreds of years ago when spinel was found together with sapphire and ruby it was impossible to tell them apart.

Spinel vs sapphire hardness. It may be colorless but is usually various shades of pink rose red blue green yellow brown black or. Corundum left a scratch on the surface of apatite and so this mineral should sit higher on the scale. Fro example corundum sapphire and ruby was used to scratch apatite. Diagnostic differences spinel ruby sapphire today gemologists understand that there are significant differences between spinel and corundum the mineral of ruby and sapphire.

Spinel like garnet diamond is singly refractive with the same physical properties in all crystal directions. The diagnostic differences are summarized in the chart on this page. The polish of gems with a mohs hardness of less than 7 can be damaged by common dust which contains tiny particles of quartz hardness 7. Gems with a hardness rating of 1 2 are considered soft while those in the range of 3 5 are medium hard.

Optical properties can also be used to distinguish spinel from corundum. Blue spinel vs sapphire. Gems over 6 are considered hard and thus suitable for jewelry. 7 is the hardness of quartz which is the hardest mineral that is commonly air born.

Spinel crystallizes in the isometric system. Spinel has been making a name for itself over the last couple of decades and demand for fine stones well exceeds supply. Danburite with a hardness rating of 7 and petalite with a hardness of 6 to 6 5 are also attractive. Goshenite has very good hardness 7 5 to 8 and is often found with excellent clarity but is not as brilliant as sapphire or zircon.

Conversely anything harder such as a sapphire ruby or diamond could scratch your spinel so it is always best to keep gemstones in soft individual cloth bags. Blue spinel hues range from violet blue through very slightly greenish blue. Of the two danburite has a higher refractive index and thus more brilliance. With modern gemological tools we can easily distinguish between blue spinel and blue sapphire.

Common crystal forms are octahedra usually twinned it has an imperfect octahedral cleavage and a conchoidal fracture its hardness is 8 its specific gravity is 3 5 4 1 and it is transparent to opaque with a vitreous to dull luster. The most important number on this scale of 7. Spinel that does not contain cobalt will not turn red. This has to some degree closed the spinel vs.