geology

Igneous Rocks: relating to, resulting from, or suggestive of the intrusion or extrusion of magma or volcanic activity; formed by solidification of magma (Merriam-Webster)

obsidian: a dark natural glass formed by the cooling of molten lava (Merriam-Webster)

pumice: a volcanic glass full of cavities and very low in density that is used especially in powder form for smoothing and polishing (Merriam-Webster)

Metamorphic Rocks: a change in the constitution of rock; specifically : a pronounced change effected by pressure, heat, and water that results in a more compact and more highly crystalline condition (Merriam-Webster)

coquina: a soft whitish limestone formed of broken shells and corals cemented together and used for building (Merriam-Webster)

limestone: a rock that is formed chiefly by accumulation of organic remains (as shells or coral), consists mainly of calcium carbonate, is extensively used in building, and yields lime when burned (Merriam-Webster)

Sedimentary Rocks: formed by or from deposits of sediment (Merriam-Webster)

gneiss: a foliated metamorphic rock corresponding in composition to a feldspathic plutonic rock (Merriam-Webster)

coal: a black or brownish-black solid combustible substance formed by the partial decomposition of vegetable matter without free access of air and under the influence of moisture and often increased pressure and temperature that is widely used as a natural fuel (Merriam-Webster)