Mineral Depot

The Gemstone Aquamarine

admin — Thu, 31 May 2007 23:29:27 +0000

Aquamarine is a blue variety of Beryl mineral with chemical composition This belongs to the mineral beryl belongs to the Silicates mineral class. Aquamarine is known member of the Beryl family. This Aquamarine is commonly used as gemstone. It usually appears in blue-green color in transmitted light of polarized light microscope. This Aquamarine is only one of the several varieties of Beryl that includes emerald, the yellow beryl called heliodor, the white beryl called goshenite, and the rose pink beryl called morganite. Other varieties are termed in accordance to their color exhibited such as the Red Beryl variety. Aquamarine is known as the most common birthstone for the month of March and also a 19th Anniversary gemstone. (more…)

Specific Gravity

admin — Thu, 31 May 2007 23:27:54 +0000

Specific gravity is synonymous with density. It is defined as the relationship between the weight of an equal volume of water and the weight of the substance. To determine by calculation, it is equal to the weight of the mineral from the air divided by its loss of weight in water. Several methods are used to determine the specific gravity of solids. These are the used of the chemical balance, sometimes called hydrostatic method; the use of the Pycnometer, the use of the heavy liquids and the Nestphal balance, the Jolly balance and the Kratsehmar direct-reading balance. (more…)

Crystal Forms and Habits

admin — Thu, 31 May 2007 23:27:29 +0000

Crystal is defined to be a definite geometrical form or outline as a result of bounding regularly arranged natural plane surfaces to a mineral or to a prepared chemical substance. Almost all gem minerals are outlined into well-formed crystals. Upon understanding the crystallographic properties of certain minerals, efficient cutting of gems is possible and of great help in the identification of uncut material. A crystal when examined under a geological polarizing microscope may appear to consist one form or have two or more forms. A form is an assemblage of corresponding faces. (more…)

Definition of a Mineral

admin — Thu, 31 May 2007 23:26:34 +0000

A mineral maybe defined as a naturally occurring inorganic homogeneous solid with a characteristics chemical composition, and usually possessing atomic structures, which can be express into crystalline formation or other physical properties visible under polarizing petrographic microscopes. The composition of a mineral is nearly constant so that assignation of chemical formula is specific. These minerals have ordered atomic arrangement with individual characteristics making them distinguishable from one another. (more…)

Chemical Composition of Minerals

admin — Thu, 31 May 2007 23:23:50 +0000

Every mineral formed is characterized by a chemical composition. Each may be classified as either a chemical compound or simply as an element. A chemical compound is formed when two or more elements are found present in a chemical combination. There are also some elements that commonly occur uncombined. These are the elements: carbon, gold, platinum, and silver. A crystallized carbon for example could turn out to be a diamond. The elements, oxygen and silicon, when combined, will form quartz, a rock crystal. The indicated chemical composition will be SiO2, silicon dioxide. Many gem minerals are characterized by exactly complex chemical formulas. (more…)