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The coral referred to in the Bible is the precious coral (Corallium rubrum), the formation of which is a calcareous secretion of certain polyps resulting in a tree-like formation. Presently coral is found in the Mediterranean , the northern coast of Africa furnishing the dark red, Sardinia the yellow or salmon-colored, and the coast of Italy ...
At surface air pressure (one atmosphere), diamonds are not as stable as graphite, and so the decay of diamond is thermodynamically favorable (δH = −2 kJ/mol). [22] However, owing to a very large kinetic energy barrier, diamonds are metastable ; they will not decay into graphite under normal conditions .
The operation of the diamond anvil cell relies on a simple principle: =, where p is the pressure, F the applied force, and A the area. Typical culet sizes for diamond anvils are 100–250 micrometres (μm), such that a very high pressure is achieved by applying a moderate force on a sample with a small area, rather than applying a large force on a large area.
Diamonds are formed under the high-pressure, high-temperature conditions of the Earth's mantle. Kimberlites act as carriers for these diamonds, transporting them to the Earth's surface. The discovery of diamond-bearing kimberlites in the 1870s in Kimberley sparked a diamond rush , transforming the area into one of the world’s largest diamond ...
The process of diamonds being used for drilling ornamental beads dates back to 2nd millennium BC. Archaeologists working in Yemen have excavated beads with evidences of diamond drilling from 1200 BC to 1st century AD from the site of Hajar ar Rayhani, with double diamond drilling from 1000 to 600 BC.
Lab-grown diamonds of various colors grown by the high-pressure-and-temperature technique. A synthetic diamond or laboratory-grown diamond (LGD), also called a lab-grown diamond, [1] laboratory-created, man-made, artisan-created, artificial, synthetic, or cultured diamond, is a diamond that is produced in a controlled technological process (in contrast to naturally formed diamond, which is ...
Ruby spectra R1, R2 lines. The ruby fluorescence pressure scale is an optical method to measure pressure within a sample chamber of a diamond anvil cell apparatus. [1] Since it is an optical method, which fully make use of the transparency of diamond anvils and only requires an access to a small scale laser generator, it has become the most prevalent pressure gauge method in high pressure ...
Since diamonds have high strength and low reactivity with either the inclusion or the volcanic host rocks which carry the diamond to the Earth's surface, the diamond serves as a container that preserves the included material intact under the changing conditions from the mantle to the surface. Although diamonds can only place a lower bound on ...