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The clarity, or purity, of a diamond refers to internal inclusions of the diamond, and is one of the 4-Cs in determining a diamond's value.Common inclusions that appear inside diamonds are black carbon spots and small cracks, commonly referred to as fractures or "feathers", due to their feathery whitish appearance when viewed from above or through the side.
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 timing of mineral crystallization can be used to categorize diamond inclusions into three types: protogenetic, syngenetic, and epigenetic inclusions. [14] Minerals in the protogenetic inclusions were crystallized earlier than the diamond formation. The host diamond encapsulated pre-existing minerals during its crystallization.
They are usually dark in color, owing to the abundance of ferro-magnesian silicates, of high specific gravity and liable to decomposition. For these reasons they have been defined as a melanocrate series (rich in the dark minerals ); and they are often accompanied by a complementary leucocrate series (rich in the white minerals feldspar and ...
Nepheline is a feldspathoid, a solid-solution mineral, that does not coexist with quartz; rather, nepheline would react with quartz to produce alkali feldspar. They are distinguished from syenites not only by the presence of nepheline but also by the occurrence of many other minerals rich in alkalis and in rare earths and other incompatible ...
Thick, unblended foundation on skin. Foundation is a liquid, cream, or powder makeup applied to the face and neck to create an even, uniform color to the complexion, cover flaws and, sometimes, to change the natural skin tone. Some foundations also function as a moisturizer, sunscreen, astringent or base layer for more complex cosmetics.
Hyperpigmentation can be caused by sun damage, inflammation, or other skin injuries, including those related to acne vulgaris. [1] [2] [3]: 854 People with darker skin tones are more prone to hyperpigmentation, especially with excess sun exposure. [4] Many forms of hyperpigmentation are caused by an excess production of melanin. [4]
The local names for the soapstone vary: in Vermont, "grit" is used, in Georgia "white-grinding" and "dark-grinding" varieties are distinguished, and California has "soft", "hard", and "blue" talc. [35] Also: Combarbalite stone, exclusively mined in Combarbalá, Chile, is known for its many colors. While they are not visible during mining, they ...