In the world of gemmology, gems are often described as belonging to a ‘family’.
One of the largest and most diverse gem families is that of the quartz group; amethyst, citrine, smoky quartz and rose quartz all belong to it.
Gemmologists describe these gems as being crystalline, in that they have large crystals usually visible to the eye.
But there is another branch in the quartz family, the cryptocrystalline gems. Jasper, agate and chalcedony are all cryptocrystalline. These gems are comprised of bundles of minute quartz fibres that require magnification to be seen.
A dense sub-microscopic structure gives cryptocrystalline gems their distinctive ‘waxy’ or ‘silky’ appearance when fashioned and polished.
Coloured by nickel, chrysoprase has a range of shades of green – from pale, soft green to darker, less bright shades. Vivid apple green is the most highly prized.
The gem’s transparency can range from semi translucent to opaque. The more translucent and bright in colour, the more appealing and valuable it is. High quality chrysoprase is described as casting a soft green ‘glow’.
It was this optical quality, along with many metaphysical properties, that made chrysoprase valued by the ancient Greeks, Romans and Egyptians. The gem was believed to ensure the wearer had good health and happiness in relationships, and prosperity in life.
 |  |
| Chrysoprase From Greek chrysos, meaning ‘gold’ and prasinon meaning ‘green’ | Colour: Green | Found in: Australia, Europe, North America, South America, Asia | Mohs Hardness: 7
Class: Chalcedony | Lustre: Vitreous, Waxy | Formula: SiO2 |
For centuries and across many cultures, chrysoprase has been valued for adornment. Polished and fashioned into cabochons, beads and other shapes, it has been worn in all manner of jewellery including cameos and intaglios.
Until the late 19th Century, the gem was popularly used for decorative items such as statues and urns, and as a luxurious feature on walls and columns in grand buildings, such as churches and palaces.
Chrysoprase is found in many countries. Significant sources are Australia (Marlborough, Queensland), Brazil, Tanzania, the US, Germany, Madagascar, Zimbabwe and India.
Sometimes called ‘Australian jade’, chrysoprase from Marlborough is highly valued in Asian markets. The gem’s similarity to quality jade with its vitreous lustre, translucency and rich, consistent colour makes it appealing.
Quality chrysoprase is increasing in value, with mines in many parts of the world being exhausted. Australia is one of the leading producers of high-quality chrysoprase.
Chrysoprase can be confused with jadeite, nephrite and prehnite – gems that have a similar translucency and colour.
There are imitants on the market, namely green glass and dyed green agate. Bubbles in the glass and irregular absorption of the dye are two indicators of imitant material.
Chrysoprase should be stored with care as its colour may fade with direct, prolonged exposure to sunlight and heat.
Although quite a durable gem – its hardness of 6.5–7 on Mohs’ scale makes it suitable for use in a wide range of jewellery – chrysoprase can be scratched by harder gems and damaged through regular wear.
To retain the gem’s beauty against the rigours of daily life, wipe gently with a clean cloth, rinse in warm water and leave to dry.