Valuing Opals

VALUING OPALS

The type, colour, size and soundness of precious opal are factors that determine the price paid for the gemstone. The price is based on the quality of the opal and expressed per carat. Furthermore, there is a marked difference between the value of uncut opal compared with the value of cut and polished opal.

Background Colour It is important to know the type of opal. Solid precious opal is more valuable than doublet or triplet opals. Black opal is more valuable than boulder opal, which in turn tends to be more valuable than light opal. The darker the body colour, the more valuable the gem.

Dominant Fire Colour The clarity of the colour is critical when assessing the value of opal. Red fire is the most rare colour, followed by green/orange, green/blue and blue. Therefore red fire opal is generally more valuable than a predominantly green opal, which in turn is more valuable than a stone showing only blue colour.

However, brilliance and clarity of an open proportioned pattern are the main decision makers - a brilliant blue/green can cost more than a dull red; bright twinkling stars of a 'pinfire' pattern can cost more than a cloudy open pattern of similar colouration; or a brilliant, lustrous light opal can cost more than a lacklustre black opal.

Colour Pattern Almost all opal displays some form of pattern. You will never find two opals that are the same. In particular, many of the top quality pieces of black opal from Lightning Ridge show their strength through a distinct recognisable pattern play of strong colours. Some of the various patterns are listed below. Harlequin Pattern: is the most prized of all patterns and is very rare. The colours in this pattern are more or less arranged like checker board squares. Floral Pattern: is possibly the most common of all nice patterns and its name is derived from its likeness to floral dress material. This pattern covers a broad range of design and colour. Pinfire Pattern: closely resembles a mass of pinheads in different colours. Palette Pattern: is like an artist's palette. Mobile Rolling Flash: usually consists of one colour that travels across part or all of the stone as it is moved. Soundness Opal should be free from cracks and flaws.