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Elbaite is allochromatic, meaning trace amounts of impurities can tint crystals, and it can be strongly pleochroic. Every color of the rainbow may be represented by elbaite, some exhibiting multicolor zonation. Microscopic acicular inclusions in some elbaite crystals show the cat's eye effect in polished cabochons.
Quartz is, therefore, classified structurally as a framework silicate mineral and compositionally as an oxide mineral. Quartz is the second most abundant mineral in Earth's continental crust, behind feldspar. [10] Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral. The transformation ...
In mineralogy, an inclusion is any material trapped inside a mineral during its formation. In gemology , it is an object enclosed within a gemstone or reaching its surface from the interior. [ 1 ] According to James Hutton 's law of inclusions, fragments included in a host rock are older than the host rock itself.
The new type of tourmaline, which soon became known as paraiba tourmaline, came in blue and green. Brazilian paraiba tourmaline usually contains abundant inclusions. Much of the paraiba tourmaline from Brazil does not actually come from Paraíba, but the neighboring state of Rio Grande do Norte. Material from Rio Grande do Norte is often ...
Most pegmatites are composed of quartz, feldspar, and mica, having a similar silicic composition to granite. However, rarer intermediate composition and mafic pegmatites are known. Many of the world's largest crystals are found within pegmatites. These include crystals of microcline, quartz, mica, spodumene, beryl, and tourmaline. Some ...
The basic level of definition is that of mineral species, each of which is distinguished from the others by unique chemical and physical properties. For example, quartz is defined by its formula, SiO 2, and a specific crystalline structure that distinguishes it from other minerals with the same chemical formula (termed polymorphs). When there ...
The word prasiolite literally means "scallion green-colored stone" and is derived from Greek πράσον prason meaning "leek" and λίθος lithos meaning "stone". The mineral was given its name due to its green-colored appearance. Natural prasiolite is a very light, translucent green. Darker green quartz is generally the result of ...
Chrome-bearing fuchsite (a variety of muscovite mica) is the classic inclusion and gives a silvery green or blue sheen. Oranges and browns are attributed to hematite or goethite . Because aventurine is a rock , its physical properties vary: its specific gravity may lie between 2.64–2.69 and its hardness is somewhat lower than single-crystal ...