Dims: 1.2 x 0.9 x 0.6" (3.0 x 2.3 x 1.5 cm)
Wt: 7.2 g
This small thumbnail specimen consists of a partly-sawn nodule of treate black Opal. This material started out as white Opal which was darkened by boiling it in a solution of sugar and sulfuric aci. It has the standard dark gray-black color and pearly-to-vitreous luster and shows only a small amount of translucence along one edge. There is a substantial amount of green and blue-green iridescence visible in the Opal, but the stone is rather dirty, with dust and grime cemented along its convex edges. There is also a substantal amount of a grainy brown matrix rock present, but the specimen is mostly opal by weight. The Opal is wet in both image, so as to take advantage of its iridescence. However, the surfaces that are not sawn have a rather shiny natural luster.