gems, lapis lazuli, Afghanistan, Tajikistan, Russia

Litsarev examines lapis lazuli as a mineral resource, with particular attention to its genesis, geological occurrence, and raw-material base. The study discusses the geological conditions under which lapis lazuli deposits form and considers their characteristics from the standpoint of exploration and economic utilization. It reviews the occurrence of lapis-bearing rocks and the factors governing the quality and distribution of usable material, relating mineralogical and geological features to the evaluation of deposits as sources of ornamental stone.