Kyanite

Kyanite is an aluminosilicate and exhibits a distinctive property, identified by its dual hardness, known as anisotropism. Kyanite most often occurs in various shades of blue. The finest variety and the most desirable is the royal blue colored variety that is very close to sapphire color, but kyanite can also be colorless, green, yellow or orange. The colorless form is the rarest, but is not the most valuable. Color is often inconsistent and unevenly distributed. Color zoning is very common in this kind of gemstone. Usually it is transparent to translucent, often with visible flaw and typical inclusions. Not very rare in small size, it become rare and expensive in size over two carats with good color and eye clean clarity. It can be found easily in cabochon duo to its frequently inclusions, or faceted in different shape, like oval or pear that preserve the major amount of material and weight. Kyanite is usually not treated and not enhanced, but some seller can treat it with oil or resin to improve clarity and luster.