Sometimes it's a complex system of technical terms, such as the specialized language used in medicine or law. In other cases, it's a less-formal system of abbreviations and acronyms. For example, job advertisements frequently use acronyms such as DOE or EOE to streamline their postings. Understanding the meaning of these and other terms can simplify the job-hunting process.
Limestone hills, Cotswolds. The Cotswold hills are made of Oolitic limestone, a type of limestone made up of small round grains. These formed in shallow, warm waters like those found today around Florida and parts of the Caribbean Sea, where calcium carbonate is deposited from sea water due to evaporation.
The large crystals that formed beneath the surface are called phenocrysts and the small crystals formed at the surface are called groundmass. Rhyolite usually forms in continental or continent-margin volcanic eruptions where granitic magma reaches the surface. Rhyolite is rarely produced at oceanic eruptions.t is usually pink or gray in color with grains so small that they are difficult to observe without a hand lens. Rhyolite is made up of quartz, plagioclase and sanidine, with minor amounts of hornblende and biotite. Trapped gases often produce vugs in the rock. These often contain crystals, opal or glassy material.