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Phantom quartz. Phantom quartz is a variety of quartz consisting of visible layers of overlapping crystal growths. The outline of the inner crystals can be seen due to some variation in composition or mineral inclusion making the boundary between growths visible. [1] The interior crystal layers are known as phantoms. Phantoms can be found in ...
Inclusion (mineral) 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. [2][3]
Inclusions can be found in these crystals that provide clues to the origins of the Herkimer diamonds. Found within the inclusions are solids, liquids (salt water or petroleum), gases (most often carbon dioxide), two- and three-phase inclusions, and negative (uniaxial) crystals. A black hydrocarbon is the most common solid inclusion. [6]
Moss agate. Moss agate is a semi-precious gemstone formed from silicon dioxide. It is a form of chalcedony which includes minerals of a green color embedded in the stone, forming filaments and other patterns suggestive of moss. [1] The field is a clear or milky-white quartz, and the included minerals are mainly oxides of manganese or iron.
A fluid inclusion is a bubble of liquid and/or gas that is trapped within a crystal. As minerals often form from a liquid or aqueous medium, tiny bubbles of that liquid can become trapped within the crystal, or along healed crystal fractures. These inclusions usually range in size from 0.01 mm to 1 mm and are only visible in detail by ...
Optical mineralogy. A petrographic microscope, which is an optical microscope fitted with cross- polarizing lenses, a conoscopic lens, and compensators (plates of anisotropic materials; gypsum plates and quartz wedges are common), for crystallographic analysis. Optical mineralogy is the study of minerals and rocks by measuring their optical ...
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO 4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO 2. Quartz is, therefore, classified structurally as a framework silicate mineral and ...
Opal is a hydrated amorphous form of silica (SiO 2 · n H 2 O); its water content may range from 3% to 21% by weight, but is usually between 6% and 10%. Due to its amorphous property, it is classified as a mineraloid, unlike crystalline forms of silica, which are considered minerals. It is deposited at a relatively low temperature and may occur ...