PURITY AND QUALITYGilsonite® uintaite is found in nearly straight, vertical veins across an area approximately 100 kilometers long and 50 kilometers wide. Gilsonite® was formed by a unique geologic event millions of years ago that caused a proto-petroleum deposit forming at that time to fill large surface cracks, later solidifying into the pure resinous rock mined today. Gilsonite® uintaite is hand-mined in underground shafts using pneumatic jack hammers. We separate Gilsonite® by temperature grade, dry and screen it, size it to customer specifications, and submit it to extensive quality control procedures before shipping to over 80 countries worldwide.