Types of Opal

There are a few different types of opal. We thought it was time to create a guide, outlining opal types which will in turn help you understand the true value of opal. 

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). Due to the potch being on the underside, when the light travels into the gem it bounces back at you — creating a super vibrant color play. These colors can be fairly vivid and intense. 

Crystal Opal

Crystal opals are found more widely across Australian Opal fields. They are characterised primarily by their semi-transparent body and tendency to have the most depth of color-on-color. When holding a crystal opal towards the light you will see that the light can pass through — unlike a black opal. 

White Opal

White opal is the most common type of opal and one that is known to most around the world. White opal is found in Australia typically around Coober Pedy but has also been 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 through but only diffused. White opals tend to exhibit more pastel colours rather than saturated color 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. It is produced in a host rock called ironstone. Boulder is much harder to mine and is not immediately obvious since it 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, this opal is a volcanic type of opal – similar to Mexican Fire Opal. At this stage nothing has been found with a play of colour but when it is faceted the light bounces beautifully around the gem.