Rocks

Dolerite, diabase, or formally microgabbro, is a dark-colored, medium-grained subvolcanic rock equivalent to basalt or gabbro in composition. Subvolcanic or

Basalt is a mafic or dark-colored, volcanic or extrusive igneous rock. Mafic refers to rocks high in dark-colored minerals rich

Thundereggs or thunder eggs are nearly spherical structures or rocky bodies filled with mineral masses or crystals in rhyolite volcanic

Druses are small to medium irregular cavities in rocks lined by small, well-formed clusters or aggregates of projecting crystals, usually

Vugs are small to medium irregular cavities, pores, or voids in rocks often lined with mineral crystals whose composition differs

Amygdales are small, round, or almond-shaped vesicles partly or fully filled with secondary minerals mostly common in volcanic or extrusive

Amygdaloidal basalts are basalt rocks with vesicles partially or fully filled with secondary minerals. The filled vesicles are called amygdales,

Andesite is an intermediate volcanic or extrusive igneous rock. Intermediate rocks are moderate in silica (52-63 wt.%), mafic, and felsic

Ultramafic is a common term in geology, GEOsciences, Earth sciences, or geography. It is commonly used in igneous rocks, their

The coarse-grained or phaneritic texture is an igneous rock texture in which you can see and distinguish individual minerals without