This amazing boulder opal specimen has a large area of green-blue opalescence and blue veining throughout the matrix - sent with information card
Australian Boulder Opal forms when silica-rich solutions seep into ironstone host rock, slowly solidifying over millions of years. As the silica spheres stack and align, they diffract light, creating the natural play-of-colour seen across the surface such as flashes of blue, violet, gold and green shifting with movement.
Unlike seam opal, Boulder Opal remains attached to its original ironstone matrix, making each piece structurally unique, shaped by the natural fractures and cavities where opalisation occurred.
