Carbonado typical gem diamonds. Lead isotope analyses have been interpreted as documenting crystallization of carbonados about 3 billion years ago. The carbonados are found in younger sedimentary rocks. Mineral grains included within diamonds have been studied extensively for clues to diamond origin. Some typical diamonds contain inclusions of common mantle minerals such as pyrope and forsterite, but such mantle minerals have not been observed in carbonado. In contrast, some carbonados do contain inclusions of minerals characteristic of the Earth's crust: these inclusions do not necessarily establish formation of the diamonds in the crust, however, because while these obvious crystal inclusions occur
Carbonado, Washington and with it came the end of the need for the lower grade coal being mined at Carbonado and the timber being harvested for use in the settlements further up the valley. Since the decline of the mining era, Carbonado has experienced extreme shrinking and small booms ultimately ending with a steady population. All of the current residents work elsewhere and what was once an economic center for the valley is now a residential community. The railroad also pulled out and destroyed its towns quite recently. The Rails to Trails project has most of the actual rail line land in