Koroit is known for their matrix boulder opals. The iron stone often appears in gorgeous patterns and if you’re lucky, there’s opal in between the layers. This one has good size, a nice pattern and a bit of color sprinkled throughout, especially visible in the Sun. Check out the video link to see more of it.
It measures 36 x 34 x 6 mm and weighs 10.9 grams.
https://youtube.com/shorts/BLzI82UDP5M?feature=share