Thanks to Wikipedia
SANDSTONE:
Sandstone is a sedimentary rock composed mainly of sand-size mineral or rock grains. Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any color, but the most common colors are tan, brown, yellow, red, gray and white. Since sandstone beds often form highly visible cliffs and other topographic features, certain colors of sandstone have been strongly identified with certain regions.
Some sandstones are resistant to weathering, yet are easy to work. This makes sandstone a common building and paving material. Because of the hardness of the individual grains, uniformity of grain size and friability of its structure, sandstone is an excellent material from which to make grindstones, for sharpening blades and other implements. Non-friable sandstone can be used to make grindstones for grinding grain, e.g., gritstone.
Rock formations that are primarily sandstone usually allow percolation of water and are porous enough to store large quantities, making them valuable aquifers. Fine-grained aquifers, such as sandstones, are more apt to filter out pollutants from the surface than are rocks with cracks and crevices, such as limestones or other rocks fractured by seismic activity.
SILTSTONE:
Siltstone is a sedimentary rock which has a composition intermediate in grain size between the coarser sandstones and the finer mudstones and shales.
MUDSTONE/SHALE:
Shale (also called mudstone) is a fine-grained sedimentary rock whose original constituents were clay minerals or muds. It is characterized by thin laminae[1] breaking with an irregular curving fracture, often splintery and usually parallel to the often-indistinguishable bedding plane. This property is called fissility. Non-fissile rocks of similar composition but made of particles smaller than 1/16 mm are described as mudstones. Rocks with similar particle sizes but with less clay and therefore grittier are siltstones. Shale is the most common sedimentary rock.
ROCK SALT:
Halite is the mineral form of sodium chloride, NaCl, commonly known as rock salt. Halite forms isometric crystals. The mineral is typically colourless to yellow, but may also be light blue, dark blue, and pink. It is chemically the same as table salt, and is often mined for that purpose.
LIMESTONE:
Pure limestone is almost white. Because of impurities, such as clay, sand, organic remains, iron oxide and other materials, many limestones exhibit different colors, especially on weathered surfaces. Limestone may be crystalline, clastic, granular, or massive, depending on the method of formation. Crystals of calcite, quartz, dolomite or barite may line small cavities in the rock.Limestone is very common in architecture, especially in North America and Europe. Many landmarks across the world, including the pyramids in Egypt, are made of limestone.
CONGLOMERATE:
Consisting of a jumble of large, gravel-like stones cemented together by sedementary action- or to be more accurate, inaction.
DOLOMITE:
Dolomite is used as an ornamental stone, a concrete aggregate and as a source of magnesium oxide. It is an important petroleum reservoir rock, and serves as the host rock for large strata-bound Mississippi Valley-Type (MVT) ore deposits of base metals (that is, readily oxidized metals) such as lead, zinc, and copper. Where calcite limestone is uncommon or too costly, dolomite is sometime used in its place as a flux (impurity remover) for the smelting of iron and steel. (Although we already knew that)
FLINT/CHERT:
Flint (or flintstone) is a hard, sedimentary cryptocrystalline form of the mineral quartz,[1][2] categorized as a variety of chert. Flint is usually dark-grey, black, or deep brown in colour, and often has a waxy appearance. It occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones.[3][4] From a petrological point of view, "flint" refers specifically to the form of chert which occurs in chalk or marly limestone. Similarly, "common chert" (sometimes referred to simply as "chert") occurs in limestone. There is much confusion concerning the exact meanings and differences among the terms "chert", "chalcedony" and "flint" (as well as their numerous varieties). In petrology the term "chert" is used to generally refer to all rocks composed primarily of microcrystalline, cryptocrystalline and microfibrous quartz. The term does not include quartzite. Chalcedony is a microfibrous (microcrystaline with a fibrous structure) variety of quartz. Strictly speaking, the term "flint" is reserved for varieties of chert which occur in chalk and marly limestone formations.
More Rocks Tomorrow!
Author
Topic: Learning about all our Dwarf Fortress Rocks! (Read 52060 times)