How do you tell the different types of opal? In this video Justin will take you through the four main Australian opal types – as well as a newly discovered one not yet gone mainstream.
Understanding opal starts with understanding the basic types of opal found.
Black opal is the most valuable type of opal and it is predominantly found in Lightning Ridge. It is called black opal due to the dark body tone of the gem. This dark body tone appears because the natural backing or tint of the stone is dark grey or black common potch (opal without colour).
With the potch on the underside the light travels into the stone but instead of passing through it bounces back at you – creating a super vibrant colour play. The colours are usually fairly vivid and intense.
Crystal opals are a more widely found across the various Australian opal fields. Crystal opals are characterised by their transparency. If you hold a crystal opal up to the light you will see that the light passes through the stone. In the video Justin shows us a beautiful crystal that displays a depth of colour which – because of the transparency – gives the gem a unique three dimensional quality. You can see the blocks of colour and patterns in the different levels of the opal. This phenomena is rarely found in other types of opal.
The most common of all the opals and the one people around the world are familiar with. White opal is found in Australia around Coober Pedy but was also found in the ancient mines of Slovakia and Hungary. It has a characteristic milky appearance and is translucent rather than transparent like crystal opal. Light can pass though but only diffused. White opals tend to exhibit more pastel colours rather than the fully saturated ones found in crystal or black opal.
Boulder opal is mainly found in the North Eastern part of Australia in the state of Queensland. The opal is found in a host rock called ironstone. As the name suggests it is much harder to mine and finds are not immediately obvious since the opal usually appears in thin seams. However, once the seams are identified and cut into large chunks, opal miners then find the fault line and “split” the rock – revealing the beautiful opal faces. This host ironstone rock can range in colour from light brown to a deep brown.
Australis Fire Opal
Currently found in the outback Western Australia this orange to yellow opal is so new it only has a marketing name! Unlike the other opals found in Australia it is a volcanic type of opal – similar to Mexican Fire Opal. At this stage nothing has been found with a play of colour but as it is faceted the light bounces beautifully around the gem. As we know more about this stone we will keep you updated.