Minerals are crystalline substances with a distinct chemical composition and orderly arrangement of their atoms, formed through three main processes. These include precipitation directly from an aqueous solution, crystallization from magma or biologic precipitation (from living organism bones).
Many minerals exhibit predictable color properties, like malachite’s green hue or azurite’s blue. But color alone cannot provide sufficient information about identifying most minerals.
Quartz
Quartz is one of the Earth’s two most abundant minerals and is present in nearly all rock types, often occurring as potassium feldspars and muscovite in igneous rocks, and in metamorphic rocks associated with calcite, dolomite and various clay minerals in metamorphic rocks; additionally it may form hydrothermal veins.
Quartz forms silica sand in sedimentary rocks, and this durable substance can be mined for use in concrete production and building materials in large amounts in Oklahoma’s Ouachita Mountains. Furthermore, this sand provides an effective’skeleton’ for soil that resists weathering as well as strong acidic conditions – perfect for building purposes and agricultural uses!
Quartz is commonly referred to by various informal names such as jasper, flint, amethyst, citrine and agate. Some types, like chalcedony are featured individually as they possess certain properties while onyx and sandstone are used in making hardstone carvings.
Feldspar
Feldspar minerals are one of the most ubiquitous rock-forming families. This grouping encompasses alkali feldspars such as albite, oligoclase and microcline (all NaAlSi3O8) as well as plagioclases like orthoclase, microcline and sanidine – distinguishable by composition; albite is sodium-rich while anorthite contains less calcium than either of them; plagioclases include both white-gray varieties like moonstone or amazonite as well as deep green microcline varieties like labradorite.
Feldspar crystals are usually tabular, flattened crystals with complex twinned layers of vitreous or pearly luster. They have excellent two-directional cleavage as well as being extremely brittle.
Feldspar is an integral component of glass and pottery glazes, and an excellent abrasive. Over time it also forms weathered forms such as china clay or kaolin that weather away to become deposits of sand and gravel deposits in dry regions – not forgetting its use in petrology to classify igneous rocks – not forgetting being essential in ceramic production as well.
Sandstone
Sandstone is an integral building material, thanks to its strength and workability, making it suitable for many different kinds of construction applications from paving to facades. Its natural beauty compliments various design styles from rustic to contemporary; while its weather resistance ensures long lifespan and reduced replacement requirements contribute to sustainable building practices.
Mature continental sediments typically comprise of quartz grains; however, other minerals such as feldspar, lithics and cementing materials (silica, calcium carbonate or iron oxide) may also be present to form the matrix of the sandstone. These provide color and texture in its clastic fraction while cementing materials (silica, calcium carbonate or iron oxide) help bind them all together into an insoluble mass known as matrix.
Matrix is a fine-grained clayey material found between framework grains in sandstones. Its source remains elusive, although possible explanations include deposition of mud in protected areas between grains, precipitation as silicate ions or alteration products of unstable grains. Hand samples typically display dark hues; thin section studies often reveal its weave-like structure with high birefringence colors.
Sulfur
Few elements have the high profile of sulfur. Due to its smelly, combustible properties — producing hydrogen sulfide gas upon burning — and association with hot springs and volcanoes, literary authors frequently used it as the symbol for hell. Today, however, most elemental sulfur production occurs byproduct-style from natural gas processing or petroleum refining operations that remove contaminants.
As it mixes readily with water, its low melting point enables scientists to use this mineral as a key component of superphosphate fertilizer production – such as that produced at Dunedin’s Ravensdown Fertiliser Works. Furthermore, its properties make it ideal for leak detection as an additive to natural gas systems, and treatment of skin conditions like scabies and dandruff.
Human bodies need sulfur in the form of methionine and cysteine amino acids to form muscle tissue and other tissues. Sulfur-rich foods like eggs, onions and garlic provide this vital element for a healthy diet.
