The Roebling Opal is an extraordinary 2,585ct piece of opal rough from Virgin Valley, Nevada. The opal was deposited from silica-rich water in voids that remained after buried tree limbs had rotted away, in some cases resulting in opal casts of the original tree parts. Although extremely beautiful, opal from this locality is not commonly used in jewelry because it tends to craze, or crack. Opals with a vivid play-of-color and a black or other dark body color are called black opals. The Roebling Opal is a black opal with flashes of blue and green play-of-color.
