Sugilite Rough Gemstone

Sugilite is a rare mineral that was discovered relatively recently and is named after the Japanese geologist Ken-ichi Sugi, who identified it in 1944. It is known for its distinctive purple color and can range from opaque to translucent. Despite sometimes being referred to as "purple turquoise," sugilite has no actual connection to turquoise.

Although sugilite stone was first identified in 1944, it didn't capture the attention of the gemstone world until much later. In 1979, a significant deposit of gem-quality sugilite was found in a manganese mine in the Southern Kalahari Desert, yielding several thousand kilograms of material.

Sugilite Square Cabochon

In mineralogical terms, sugilite is classified as a cyclosilicate, in the same class as tourmaline, iolite and the beryl group. Sugilite gemstone has a very complex chemical composition, it is potassium sodium lithium iron manganese aluminum silicate. It is only rarely found as crystals, usually being massive in form. Sugilite has a Mohs hardness of 5.5 to 6.5 and a specific gravity of 2.75 to 2.80. It has a refractive index of 1.607 to 1.61 and typically has a waxy to vitreous luster. Sugilite is not especially hard, but is quite a durable material since it has poor cleavage.

Sugilite gemstone colors include all shades of purple; from lilac to plum, including hues of magenta, purple and red-violet. Sugilite specimens often contain black matrix, and reddish or yellowish blotches, since it occurs in brownish-yellow and pale pink as well as violet and reddish-violet. Sugilite cabochons are often be found mixed with chalcedony.

Sugilite Trillion Cabochon

Sugilite deposits are found in Australia, India, Japan, Canada and South Africa.

Like most colored stones, sugilite's value is based on its color. Specimens with a vivid and intense purple are valued most highly. Since many sugilite stone specimens are multicolored, attractive patterns and veining raise the value of a piece. Sugilite is often available in large sizes, with pieces weighing over 10 carats being common.