Types of Opal

Here lays a guide to the different types of opal that can be found. To understand the true value of opal, you first need to understand how they are classified.

Black Opal

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 rich black body tone of the gem. This body tone appears because the natural backing or tint of the stone is 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 Opal

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.

White 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 is characterised by its 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

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 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.

Australian Fire Opal

Currently found in the outback of 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.