MINERAL AND ROCK

Mineral and Rock



Mineral and Rock

Mineral

A mineral, by definition, is any naturally occurring, inorganic substance, often additionally characterized by an exact crystal structure. Its chemical structure can be exact, or can vary within limits(Brunton, et al., 2005). Elements that occur naturally are also considered minerals.

All minerals belong to a chemical group, which represents their affiliation with certain elements or compounds. The classified chemical groups are known as: Elements, Sulfides, Oxides, Halides, Carbonates, Nitrates, Borates, Sulfates, Chromates, Phosphates, Arsenates, Vanadates, Tungstates, molybdates, and Silicates. Some of these chemical groups have sub-categories, which may be categorized in some mineral references as separate groups.

Rock

The best way to define a rock is to say that it is an indefinite mixture of naturally occurring substances, mainly minerals(DeMouthe, 2006). Its composition may vary in containment of minerals and organic substances, and are never exact. They can range from tiny microscopic grains of minerals or organic substances to coarse agglomerates of different minerals, where the individual minerals are easily discernible.

They may range in size from tiny pebbles to huge mountains. Rocks make up the earth's crust. Many rocks are not solid -- such as magma, soil, and clay(Croucher, Wooley, 2007). In general, the only people interested in rocks are geologists and paleontologist who are interested in the scientific nature and dating of the rocks.

The term "rock collection" is usually misused for "mineral collection". Although a few people collect rocks, the amount of people collecting minerals is much greater.

Glory of Rock and Mineral Identification Microscopy

Rock and mineral identification microscopy has always been the subject of the entirety of geology. Scientists focus on the discovery of manners that could further introduce different matter and distinguish them from one another.

Factors Considered in Rock and Mineral Identification

Rock and mineral identification microscopy considers six factors: relief, shape and cleavage, color and “pleochroism,” opacity, vibration directions, birefringence, and interference colors(Embry, 2007). These six are what researchers in the field of rock and mineral identification microscopy look for.

Relief is the property of minerals and rocks to appear visible immediately, wherein the details of the material's texture, surface and cleavage are noticed, while other minerals look like colorless and featureless stones that are barely visible.

Rock and mineral identification microscopy tells the story of what the billion-year-old Earth really is. How is provides nutrients to us and why its land structure is beneficial or not. Without such exploration everything about Earth will remain unknown like the depth of the universe and the possibility of life beyond Earth(Dunn, et al., 2008).

Physical Properties Used for Mineral Identification

Color - pigment of fresh mineral surface in white light

“fresh” = clean and untarnished (tarnished color can be mentioned but it is not the true color of the mineral)

Streak - color of mineral in powdered form on an unglazed porcelain plate (“streak plate”)

Luster - how a fresh mineral surface reflects light (NOT how it transmits light) “metallic” - looks like a shiny metal

“submetallic” - looks like a duller metal “nonmetallic” - all others, ...