The ability to etch nanostructures onto the surface of diamond is expected to have a wide variety of potential applications, but so far etching and patterning diamond at the nanoscale has been challenging, as diamond is highly ...
Researchers have discovered a metal alloy that can conduct electricity with zero resistance, or superconduct, from ambient pressure up to pressures similar to those that exist near the center of the Earth. The material, which ...
(Phys.org)—For the first time, researchers have demonstrated that shining a nanosecond pulsed laser at the base of a 100-µm-long diamond needle can significantly enhance electron emission from the tip of the needle. The ...
(Phys.org)—Researchers have finally answered a question that has eluded scientists for years: when exposed to moderately high pressures, why does graphite turn into hexagonal diamond (also called lonsdaleite) and not the ...
(Phys.org)—By carefully placing a tiny piece of diamond within a few nanometers of a carbon nanotube, and then sending an electric current through the nanotube, researchers have designed a device that could one day form ...
(PhysOrg.com) -- By applying extreme pressure to compress and flatten carbon nanotubes, scientists have discovered that they can create a new carbon polymer that simulations show is hard enough to crack diamond. The pressure-induced ...
(PhysOrg.com) -- Carbon comes in many different forms, and now scientists have predicted another new form, or allotrope, of carbon. The new form of carbon, which they call T-carbon, has very intriguing physical properties ...
(PhysOrg.com) -- To build a quantum computer, it's essential to be able to quickly and efficiently manipulate the quantum states of qubits. The qubits, which are the basic unit of quantum information, can be composed of many ...
(PhysOrg.com) -- Currently, diamond is regarded to be the hardest known material in the world. But by considering large compressive pressures under indenters, scientists have calculated that a material called wurtzite boron ...
Condensed Matter
Feb 12, 2009
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A new study has found that "diamond rain," a long-hypothesized exotic type of precipitation on ice giant planets, could be more common than previously thought.
Planetary Sciences
Sep 2, 2022
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In mineralogy, diamond (from the ancient Greek αδάμας – adámas "unbreakable") is an allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is less stable than graphite, but the conversion rate from diamond to graphite is negligible at ambient conditions. Diamond is renowned as a material with superlative physical qualities, most of which originate from the strong covalent bonding between its atoms. In particular, diamond has the highest hardness and thermal conductivity of any bulk material. Those properties determine the major industrial application of diamond in cutting and polishing tools.
Diamond has remarkable optical characteristics. Because of its extremely rigid lattice, it can be contaminated by very few types of impurities, such as boron and nitrogen. Combined with wide transparency, this results in the clear, colorless appearance of most natural diamonds. Small amounts of defects or impurities (about one per million of lattice atoms) color diamond blue (boron), yellow (nitrogen), brown (lattice defects), green (radiation exposure), purple, pink, orange or red. Diamond also has relatively high optical dispersion (ability to disperse light of different colors), which results in its characteristic luster. Excellent optical and mechanical properties, combined with efficient marketing, make diamond the most popular gemstone.
Most natural diamonds are formed at high-pressure high-temperature conditions existing at depths of 140 to 190 kilometers (87 to 120 mi) in the Earth mantle. Carbon-containing minerals provide the carbon source, and the growth occurs over periods from 1 billion to 3.3 billion years (25% to 75% of the age of the Earth). Diamonds are brought close to the Earth surface through deep volcanic eruptions by a magma, which cools into igneous rocks known as kimberlites and lamproites. Diamonds can also be produced synthetically in a high-pressure high-temperature process which approximately simulates the conditions in the Earth mantle. An alternative, and completely different growth technique is chemical vapor deposition (CVD). Several non-diamond materials, which include cubic zirconia and silicon carbide and are often called diamond simulants, resemble diamond in appearance and many properties. Special gemological techniques have been developed to distinguish natural and synthetic diamonds and diamond simulants.
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