Australian Boulder opals are found in unlikely places, such as cracks, crevices, and cavities.

A Reddit user (u/adymma90) came across a piece of petrified wood in Queensland, Australia that was full of the beautiful gem – and we’re not surprised the photo went viral.

The inside of the wood contained a beautiful structure of the iridescent turquoise opal.The original post has been upvoted over 90,000 times, in part because very few people had ever seen anything like it.

The opal inside this piece of petrified wood is basically the mineral concentration of it.

Orals can form in other unexpected places as well. For example, archeologists have already found numerous shells and bones that were completely opalized, and the result is basically just as mind-blowing as the picture in question.

The way the mineral looks inside this piece of wood can almost be described as magical. It might even make you wonder how opal is formed in the first place.

These opals often form the basis for organic gemstones, and you’ll often find them reworked somehow into beautiful jewelry such as opal rings and necklaces.

The forming of opal is a completely natural, yet lengthy process.

The substance itself is actually a solution of water and silicon dioxide. That silica is transported and picked up from sandstone via the water, which then carries it into all sorts of voids and cracks. These cracks are often decomposing fossils, or sometimes just natural faults.

The water that carries these silica elements eventually evaporates, and leaves all the silica behind. In this case, wood can start a petrifaction process underneath the ground.

According to Geology.com, volcanic ashfall is the ideal environment for opal and petrified wood to form.

“One of the most common and best geologic environments for the formation of petrified wood is a forest buried by a volcanic ashfall. In this situation the ash buries the plants and protects them from decay and insect attack. The ash also serves as an abundant source of easily dissolved silica, which will be carried into the wood by moving groundwater where it precipitates in cavities and replaces the solid woody materials,” the website writes.

This pure form of opal is absolutely beautiful and is a popular and expensive mineral that is often used in jewelry and works of art.

The word ‘opal’ actually derives from the Greek word “Opallios”, which loosely translates to “perceiving a change of color.” When you shine light on an opal, it has the tendency to change color, making the whole thing even more spectacular.

In certain areas in Australia, opal is a lot less rare than in the rest of the world.

In particular, you’ll find a lot of Boulder Opal pieces, which are sometimes referred to as “Rainbow Tree” stones because of their color-changing abilities.

It’s not hard to see why specialized mines were built in the late 19th century to get as much opal as possible.