Gahnospinel

Another specialty gem type found mainly from Sri Lanka. These are closely related to gems called spinals which are very very common in mines. But Gahnospinel are very very rare. Even after finding them , precise identification of this gem type is even more difficult.

Spinals when checked from surface they appear as bi-pyramid lattice. But Gahnospinel have spherical and oval lattices. This is called Pebble effect. These gems are usually found in rivers. While spinals are common in Red , Blue , Yellow and Pink but Gahnospinel have shiny color. Its different to Blue Spinals and electric blue color of Cobalt Spinals. Its much closer to Royal Blue color of blue sapphire. Gahnospinel have very high refractive index of 1.74.

An expert on gems can clearly identify this quality. These are not sharp has Blue sapphires, but more sharper than regular blue spinals. Refraction index testing can clearly identify Gahnospinel. Even though chemically spinals are classified into many chemicals, Gahnospinel contain Mg. Zh, Al and Co. Refraction index may range from 1.735 to 1.745. But they are uni refractive. Specific Density is between 3.65 and 4.55. Color can also vary from shiny blue to purple because of Fe ions in the gem. Contrasting color of Gahnospinel can also be little darker too. They are rarely discovered in Madagascar as well.