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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.
Breyite is a high pressure calcium silicate mineral (CaSiO 3) found in diamond inclusions. [3] [4] It is the second most abundant inclusion after ferropericlase, for diamonds with a deep Earth origin. [5] [4] Its occurrence can also indicate the host diamond's super-deep origin. This mineral is named after German mineralogist, petrologist and ...
Smaller deposits are found in South America (Brazil and Bolivia), Portugal, Romania, Burma and Russia. Hackmanite is found principally in Mont-Saint-Hilaire and Greenland. Euhedral, transparent crystals are found in northern Namibia and in the lavas of Vesuvius, Italy. Sodalitite is a type of extrusive igneous rock rich in sodalite. [16]
A mafic mineral or rock is a silicate mineral or igneous rock rich in magnesium and iron. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks include basalt, diabase and gabbro. Mafic rocks often also contain calcium-rich varieties of plagioclase ...
Speaking broadly, mineral color points out the specific gravity of the mineral, as minerals that are lighter in color tend to be less dense. Darker minerals typically tend to contain more of relatively heavy elements, notably iron, magnesium, and calcium. [2] The temperature of crystallization affects what the color index of rocks tends to be. [10]
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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 ...