Gold Sheen Sapphire Grading
The following grading system for Gold Sheen Sapphire was developed by Steve Waddington and Tanzim Khan Malik. The purpose is to be able to fully describe the unique characteristics of gold sheen sapphire, and to accurately reflect its value to buyers.
- Commercial – Noticeable blemishes that distract from striation and/or compromise the gems structure. Opaque to semi-translucent.
- Good – Small, but eye visible blemishes otherwise masked by striation that do not compromise structure. Semi-translucent to semi-transparent.
- Very Good – sub-grade, nearing Fine grade
- Fine – No eye visible blemishes. Translucent to semi-transparent.
- Very fine – sub-grade, nearing Exceptional grade
- Exceptional – No loupe visible blemishes. Semi-transparent.
In addition to normal colours, gold sheen sapphire may exhibit the following colours:
- Gold – matching the gold colour of pure gold, or pyrite
- Electrum – the colour half way between gold and silver
- Bronze – The colour half way between gold and copper
- Copper – the colour of polished copper
Each stone is described by its primary body colour, ie its predominant colour, secondary body colour, and other colours present.
Striation is the most prominent feature of many GSS stones. It is present in some degree in all GSS and can range from full hexagonal windows, precise geometric lines, to small, almost invisible, curving irregular lines of any length.
There are three types of striation:
- Linear – straight lines of varying width, sometimes intersecting at 120 degrees
- Hexagonal – Full or partial, where there are two or more 120 degree linear intersections
- Crazing – irregular curving lines of any length
Striation may be:
- Prominent – A significant feature of the stone.
- Minor – easily visible, but not a significant feature
- Very Minor – eye visible only on close examination
One or more types of striation may be present in a stone. Most GSS over 0.5ct will have prominent striation, smaller stones will tend to be minor to very minor.