Contains pyrite and might contain some calcite Chilean—Often tinged or spotted with green, with obvious calcite matrix A gemstone’s appearance might be described using an adjective that refers to a ...

Lapis frequently contains varying amounts of whitish calcite matrix—the host rock that surrounds the gem—or flecks or veins of glinting yellow pyrite, or both. The gem can also have a smoothly uniform ...

dolomite and calcite cement between the sediment grains of the reservoir rocks. There are two types of acid treatment: matrix acidizing and fracture acidizing. A matrix acid job is performed when ...