Star Diopside Gems: The Black Star of India

The diopside gemstone group is most famed for its chrome green member known in the trade as 'chrome diopside', but 'star diopside', a chatoyant black to greenish black diopside is also highly sought after and treasured by gem collectors, owing to its uniqueness. Black star diopside is sometimes traded as "Black Star of India". Although it is typically black or blackish-green, on rare occasion, star diopside can be true green. Star diopside may sometimes be confused with similar colored gemstones such as hiddenite, moldavite, peridot, emerald or idocrase. Black star sapphire is often confused with black star diopside, but can be easily distinguished by its hardness and the differences in asterism (the star effect), as explained below.

Star Diopside Cabochon

Like other forms of diopside, star diopside is composed of calcium magnesium silicate. It is fairly soft compared to most other gemstones with a hardness of just 5 to 6 on the Mohs scale. Therefore, its use in gemstone jewelry should be limited to cabochon earrings, pendants or star cabochon rings, and worn with care. Star diopside has an attractive vitreous luster and is normally cut into oval or round cabochons to maximize weight and chatoyancy. The cabochons are typically biconvex and the bottoms are left rough and unpolished. Star diopside has a specific gravity (density) ranging from 3.22 to 3.38 and a refractive index of 1.664 to 1.730. It belongs to the monoclinic crystal system and is known to form as columnar crystals.

Star diopside has a very unique asterism compared to other types of star gemstone. It can also form with cat's eye chatoyancy, but asterism is more common. The white star can be easily seen against the dark diopside body color, and the asterism displayed is quite unique -- in that it only exhibits four rays; most star gemstones feature six-ray asterism, but star diopside's four rays are a result of its binary symmetry. In addition, star diopside's rays are crooked and slightly wavy because they are not at 90° right angles.

Star Diopside with Magnetite Inclusions

With star diopside, the needle-like inclusions responsible for the asterism are often visible from the surface of the stone. In fact, specimens are sometimes so heavily included with crystals of magnetite that they can be easily attracted to magnetic forces, since magnetite is the most magnetic mineral on Earth. Since it can carry such strong magnetism, star diopside is actually very popular for therapeutic use, particularly in crystal healing and metaphysical practices.

When it comes to the meanings associated with gemstones, star diopside is believed to rejuvenate the body, soul, and mind. Its powerful magnetic properties are thought to assist in physical healing, especially when placed close to the skin near the affected area. It is believed to have positive effects on the lungs, heart, and circulatory system, as well as potentially aiding in psychological disorders. Star diopside is also known as the "crying stone" for its purported ability to evoke tears as a way to release emotions. Some believe it can help with issues like aggression, trauma, love, and commitment, while others think it can enhance creativity in the wearer.

Today, most star diopside material comes from India, which is how it earned its nickname 'the Black Star of India'. However, smaller deposits of star diopside have been discovered in other areas, including Austria, Finland, Madagascar, Myanmar (Burma) South Africa, Sri Lanka and the United States.