(ËlÉk tÉrn) n. 1. a reading desk in a church from which the Bible lessons are read during the service. 2. a stand with a slanted top, used to hold a book, speech, etc., at the proper height for a standing reader or speaker.
How a Diamond is Formed. In order for diamond to form there must be an available source of carbon and relatively narrow ranges of temperates and pressures must align. This happens around 100 miles below the crust. Once crystalized the diamonds must be rapidly transported to the surface without undergoing substantial change.
Diamonds typically occur in a rock called Kimberlite and in related cousins (Lamproite). Although diamond crystals are found in Kimberlite and related rocks, the origin of diamond is more closely related to the fragments of peridotite and eclogite which are derived from the upper mantle, below cratonic (shield) areas.iamonds typically occur in a rock called Kimberlite and in related cousins (Lamproite). Although diamond crystals are found in Kimberlite and related rocks, the origin of diamond is more closely related to the fragments of peridotite and eclogite which are derived from the upper mantle, below cratonic (shield) areas.