Where do sapphires come from?
Fossicking for Sapphires
Sapphires are formed out of the mineral corundum and the magma cooling process. The formation process can take millions of years. The longer it takes for these crystals to cool, the bigger the sapphire will be. There are a number of different transition minerals which will seep into these crystals while forming. Different mixtures of minerals will give sapphires their distinct range of colours.
Millions of years ago, intense heat and pressure 20-50kms under the earths surface created a number of sapphire deposits. Experts believe sapphires appeared on the surface due to volcanic eruptions, tectonic plate movement and intense weathering over long periods of time. Ancient floods carried these stones into forgotten river beds and even some still active river systems.
How do you find sapphires?
Depending on your location, the types of sapphire fossicking are; Flowing Creek Bed, Ancient Creek Bed and Specking.
Your main objecting when looking for sapphires is to locate the wash layer.
Example of wash layer:
Sapphires are heavier than normal stones. Over a long period of time they will gradually sink to the bottom of the once flowing river bed. Although sapphires are found throughout the wash your best chance will be on top of the bedrock or clay layer.
A water supply is essential when fossicking for sapphires. Unless you are working a flowing creek bed you will need to bring your own water to clean the wash.
The Sapphire Rainbow
The art of sieving
How are Sapphires valued?
Many factors are taken into consideration when valuing a sapphire.
- Size - The larger the stone the more it's worth per ct. A perfect royal blue 1ct cut sapphire can be worth anywhere from $300-500 per ct. The more your sapphire weighs, the greater it's value per ct. Larger stones can be worth anything from $1,000-$10,000+ per ct. Rough sapphires are worth significantly less.
- Colour - Rare colours also impact the value of a sapphire. Cornflower Blue, Orange and Pink are the most valuable. Some people are lucky enough to find multi-coloured sapphires which are known as parti sapphires.
- Clarity - Your sapphires must be transparent! If you cannot see through your sapphire, then unfortunately it's a bomb!
- Inclusions - Too many inclusions or too much silk will lower the value of your sapphire. Inclusions are tiny minerals trapped inside the sapphire which also effect it's colour.
- Shape - You may find the perfect colour and perfect clarity sapphire, but unless it's shaped for faceting it may not be worth as much as you think. Dog tooth sapphire crystals make the best shape for faceting.
- Treatment - If your sapphire is too dark, it's possible to have it heat treated. However this does significantly lower it's value.
Equipment
Only hand tools are permitted in public fossicking areas. Big fines apply for those caught using power tools and machinery.
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