65.30 ct Koroit Boulder Opal
$100.00
Skip to product information
65.30 ct Koroit Boulder Opal
$100.00
65.30 ct Koroit Boulder Opal
Koroit boulder opal is a highly prized type of boulder opal mined exclusively from the remote Koroit opal field in southwest Queensland, Australia.
Boulder opal forms when precious opal fills cracks, veins, cavities, or voids within a natural host rock—typically dark ironstone (a hard, brownish matrix). Unlike seam or black opals that form in softer clay or sandstone, boulder opals retain part of this tough ironstone backing, which gives them durability and a distinctive look.