Chrysoberyl Gemstones – Properties, Origins, Treatments and Buying Guide

Chrysoberyl is one of the most durable and eye-catching gemstones, prized for its bright yellow, golden, greenish, and rare cat’s eye effects. Unlike soft or easily scratched stones, chrysoberyl is tough, highly refractive, and valued for its brilliance and clarity.

In this guide we examine chrysoberyl from a professional gemmological and commercial perspective, covering its physical properties, crystal structure, treatments, origins, and how to identify fine-quality stones.

Chrysoberyl is a hard, durable gemstone composed of beryllium aluminium oxide (BeAl₂O₄). It occurs in orthorhombic crystals, often forming elongated prismatic shapes. The most famous variety, cat’s eye chrysoberyl (cymophane), exhibits a sharp, bright chatoyancy caused by fibrous inclusions.

Chrysoberyl has the chemical formula:

BeAl₂O₄

This means it is composed primarily of:

Beryllium
Aluminium
Oxygen

Trace elements such as iron may influence colour, while fine fibrous inclusions produce the cat’s eye effect in cymophane.

Chrysoberyl belongs to the oxide mineral family.

Its crystal system is orthorhombic, producing long prismatic crystals ideal for faceting and chatoyancy effects.

Chrysoberyl combines high brilliance, clarity, and exceptional durability, making it a premium gemstone for fine jewellery and collector specimens.

Lustre
Vitreous to adamantine, giving intense sparkle.

Transparency
Transparent to translucent; gem-quality stones are highly transparent.

Refractive index
1.746 – 1.755, providing high brilliance.

Specific gravity
3.73 – 3.78, typical of hard oxide gemstones.

Chrysoberyl occurs in a range of colours:

Golden yellow
Honey
Greenish-yellow
Brownish
Colourless
Cat’s eye (cymophane) with silky band

The most valuable stones have clear colour, high transparency, and sharp chatoyancy in the cat’s eye variety.

Chrysoberyl has a Mohs hardness of 8.5, making it exceptionally durable and suitable for all types of jewellery, including rings.

It has excellent toughness and resists scratching better than many gemstones of similar beauty.

Most chrysoberyl is untreated. Rarely, heat treatment may be applied to improve colour uniformity. No fracture fillings or coatings are used in high-quality stones.

Avoid harsh chemicals.
Warm water, mild soap, and soft brush are recommended.
Ultrasonic cleaning is generally safe, except for cat’s eye stones with inclusions.
Store separately from harder stones like sapphire and diamond.

Major sources of chrysoberyl include:

Brazil
Sri Lanka
Madagascar
Myanmar
Tanzania
Russia