Hallmarks: 925 The Honduran black opal is a unique variety of matrix opal. Stones are beautifully speckled and appear almost galactic in nature. They are of volcanic origin forming in basalt belts which gives them their dark body color. As with every opal, the colors and patterns of each stone are never exactly alike and Honduran black opal is no exception. This particular stone is more grey/brown in coloration. Pictures are enlarged to show detail please refer to the photos with measurements for true approximate dimensions. Colors may vary by monitor settings and lighting. Please ask questions BEFORE you buy an item.