Cabochons › Boulder Opal with Hematite Image 1 of 3 Image 2 of 3 Image 3 of 3 Boulder Opal with Hematite $40.00 18.5ct, 11mm x 27mm freeform Boulder Opal with Hematite cabochon with large pockets of electric blue flashes down the front. Add To Cart Added! 18.5ct, 11mm x 27mm freeform Boulder Opal with Hematite cabochon with large pockets of electric blue flashes down the front.