Buffalo Head Hills kimberlite field They have a low carbonate content, low abundances of late-stage minerals such as phlogopite and ilmenite, and a high abundance of fresh, coarse olivine. Based on examination of more than 700 examples, the BHH diamonds range in color from colorless to yellow and brown, and most are transparent and colorless. The majority are sharp-edged octahedra, but ~45% were dodecahedral due to resorption of octahedra. Inclusions of garnet, olivine, clinopyroxene and rutile were found in a few specimens. Buffalo Head Hills kimberlite field The Buffalo Head Hills kimberlite field is a group of kimberlitic volcanic pipes or diatremes in north-central Alberta,
Black Rock Desert volcanic field through geologic faults. Black Rock Desert volcanic field The Black Rock Desert volcanic field in Millard County, Utah, is a cluster of several volcanic features of the Great Basin such as Pavant Butte and Tabernacle Hill. The field's Ice Springs event was an explosive eruption followed by lava flows that were Utah's most recent volcanic activity (1140–1440 AD). which overlapped the older flows of Pavant Butte. The Pleistocene-Holocene field has been an active tectonic area for approximately 2.7 million years. Within the past 1.5 million years, local volcanism has produced both rhyolitic and basaltic cones from near twenty-four vents from