Types of Opals

Types of Opals

Opals are a stunning gemstone that come in an array of colours, shapes, sizes and patterns. There are so many different types of opals and we use so many of them in our jewellery. Knowing the differences between each type of opal deepens anyone’s appreciation and awe of these magnificent stones.


Boulder Opal

These opals are predominately mined here in Queensland! As the name suggests, they are formed within crevices and fractures in ironstone and sandstone boulders. The opal is naturally attached to these ‘host rocks’ which are mined with the opal. This creates many organic and uniquely shaped gemstones that highlight the intricacies of nature.

We have another article where you can read more about Australian Boulder Opals.

Matrix Opal

Matrix Opals are similar to Boulder Opals in the way they are formed within boulders, however, they are formed in the infillings of pores or holes between grains of the host rock. This creates many intricate patterns and designs as the natural shapes of the rocks are emphasised by bursts of vibrant opal colours. Boulder Matrix Opals are found exclusively in Queensland and are differentiated by the ironstone host rock.


Black Opal

Black opals are distinguished by their dark or black tone. This can been seen in blackness in the opals background in comparison to other colours featured in the gemstone. Though they have dark tones, they can still be very colourful. The blackness of the background makes the colours pop even more! Black opals are the darkest and most valuable form of opals.

 Lightning Ridge Opal

Mined in Lightning Ridge in New South Wales, this mine is world famous for quality opals. Some of the most valuable black opals have been mined here, giving this mine its reputation.


White Opal

As opposed to black opals, white opals have base tones that range from colourless to light grey. Typically, white opals have a colour that appears quite milky. Many bright colours are illuminated when this opal is in the light as it catches more of the colours that are within the milky white opal.

Crystal Opal

These opals usually appear as fully transparent or translucent, resembling a glassy appearance. Crystal opals include black, white, and many other types of opals with greater transparency. They can often display colours of opals more vibrantly, in comparison to opaque stones, as they have more clarity.

However, Boulder Opals are not technically classified as crystal opals, even if they have a glassy appearance because of the ironstone backing they usually have.

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