Instruct: Given a question, retrieve documents that answer the question.
Query: What types of diamonds are there?
Diamond type is a method of scientifically classifying diamonds by the level and type of their chemical impurities. Diamonds are separated into four types: TypeIa, TypeIb, TypeIIa, and TypeIIb. The impurities measured are at the atomic level within the crystal lattice of carbon atoms and so, unlike inclusions, require an infrared spectrometer to detect.[1]
Diamond is the allotrope of carbon in which the carbon atoms are arranged in the specific type of cubic lattice called diamond cubic. Diamond is an optically isotropic crystal that is transparent to opaque. Diamond is the hardest naturally occurring material known. Yet, due to important structural weaknesses, diamond's toughness is only fair to good. The precise tensile strength of diamond is unknown, however strength up to 60 GPa has been observed, and it could be as high as 90–225 GPa depending on the crystal orientation. The anisotropy of diamond hardness is carefully considered during diamond cutting. Diamond has a high refractive index (2.417) and moderate dispersion (0.044) properties which give cut diamonds their brilliance. Scientists classify diamonds into four main types according to the nature of crystallographic defects present. Trace impurities substitutionally replacing carbon atoms in a diamond's crystal structure, and in some cases structural defects, are responsible for the wide range of colors seen in diamond. Most diamonds are electrical insulators but extremely efficient thermal conductors. Unlike many other minerals, the specific gravity of diamond crystals (3.52) has rather small variation from diamond to diamond.
There is a supplemental letter from the Gemological Institute of America stating that the diamond has been determined to be a Type IIa diamond. Type IIa diamonds are the most chemically pure type of diamond, and often have exceptional optical transparency. Type IIa diamonds were first identified as originating from India, particularly from the Golconda region, but have since been recovered in all major diamond-producing regions of the world. Famous examples of Type IIa diamonds are the 530.20 carat Cullinan I and the 105.60 carat Koh-i-noor.
The supplemental letter from the GIA is accompanied by a monograph from the Gemological Institute of America which features additional photographs, data collection charts and gemological research which details the rarity of the Elizabeth Taylor Diamond.
The Briolette of India is a colourless (D-coloured), clear diamond. It is cut in a briolette shape, an exaggerated form of double rose cut. The diamond weighs . It is D-color and a type IIa diamond, which are the purest type of diamonds with no chemical impurities or plastic deformations in the crystal. Because of its pureness, it is even known as the "purest of the pure". When last seen, the diamond was being used as the pendant of a necklace, along with another diamond and a large pearl.
Bezel settings for diamond rings are also called rub-over settings; they have a diamond completely surrounded by a precious metal band which fastens the diamond securely into place. Bezel settings use a type of elevated collar which wraps the rim of the diamond in a complete metal edging. This type of diamond rings setting is the most secure fastener for the stones. The bezel setting also protects the diamond better than other types of settings, such as the prong setting. A flush setting for diamond rings is a variation on the rub-over or bezel setting. In the flush setting, the stone is placed into an opening and affixed at the bottom of the stone. The top of the diamond is extended above the base.
The Argyle diamond mine is located in North of Western Australia. It produces over 90 percent of the world's pink diamonds; 0.1% of diamonds in the mine are classified as pink. The pink diamond comes in shades ranging from a pastel rose, such as the Pink Orchid, to intense purple-reds such as the Moussaieff Red Diamond. The price is determined by the intensity of the color. Pink diamonds have sold for up to $1,000,000 a carat. Unlike the Type I diamonds, which derive their color from impurities, pink diamonds are Type II and get their color from a process known as plastic deformation.
The GIA Laboratory provides a variety of gem grading and identification reports. Diamond grading reports for unmounted natural and synthetic diamonds determine their key characteristics: color, clarity, cut and carat weight. GIA issues two types of reports, the more complete being the Diamond Grading Report (a briefer and less expensive version is called a Diamond Dossier). The reports contain a number of measurements, including of carat weight as well as a diagram of where and what types of inclusions are located in the diamond. Diamond grading reports are now demanded by most consumers purchasing diamonds over a certain size, typically for over 0.5 carat (100 mg), and almost always for over 1.0 carat (200 mg), and are considered an important tool in guaranteeing that a diamond is accurately represented to a potential buyer.
Type I diamond has nitrogen (N) atoms as the main impurity, at a concentration of up to 1%. If the N atoms are in pairs or larger aggregates, they do not affect the diamond's color; these are Type Ia. About 98% of gem diamonds are type Ia: these diamonds belong to the "Cape series", named after the diamond-rich region formerly known as Cape Province in South Africa, whose deposits are largely Type Ia. If the nitrogen atoms are dispersed throughout the crystal in isolated sites (not paired or grouped), they give the stone an intense yellow or occasionally brown tint (type Ib); the rare canary diamonds belong to this type, which represents only ~0.1% of known natural diamonds. Synthetic diamond containing nitrogen is usually of type Ib. Type Ia and Ib diamonds absorb in both the infrared and ultraviolet region of the electromagnetic spectrum, from 320 nm. They also have a characteristic fluorescence and visible absorption spectrum (see Optical properties).
Type II diamonds have very few if any nitrogen impurities. Pure (type IIa) diamond can be colored pink, red, or brown owing to structural anomalies arising through "plastic deformation" during crystal growth; these diamonds are rare (1.8% of gem diamonds), but constitute a large percentage of Australian diamonds. Type IIb diamonds, which account for ~0.1% of gem diamonds, are usually a steely blue or gray due to boron atoms scattered within the crystal matrix. These diamonds are also semiconductors, unlike other diamond types (see Electrical properties). Most blue-gray diamonds coming from the Argyle mine of Australia are not of type IIb, but of Ia type. Those diamonds contain large concentrations of defects and impurities (especially hydrogen and nitrogen) and the origin of their color is yet uncertain. Type II diamonds weakly absorb in a different region of the infrared (the absorption is due to the diamond lattice rather than impurities), and transmit in the ultraviolet below 225 nm, unlike type I diamonds. They also have differing fluorescence characteristics, but no discernible visible absorption spectrum.
Diamond dressers consist of single-point or multipoint tools brazed to a steel shank, and used for the trueing and dressing of grinding wheels. The tools come in several types, including: grit impregnated, blade type, crown type, and disc type. The advantages of multipoint over single-point tools are:Polycrystalline diamond (PCD) is formed in a large High Temperature-High Pressure (HT-HP) press, as either a diamond wafer on a backing of carbide, or forming a "vein" of diamond within a carbide wafer or rod.
A diverging diamond interchange (DDI), also called a double crossover diamond interchange (DCD), is a type of diamond interchange in which the two directions of traffic on the non-freeway road cross to the opposite side on both sides of the bridge at the freeway. It is unusual in that it requires traffic on the freeway overpass (or underpass) to briefly drive on the opposite side of the road from what is customary for the jurisdiction. The crossover "X" sections can either be traffic-light intersections or one-side overpasses to travel above the opposite lanes without stopping, to allow nonstop traffic flow when relatively sparse traffic.
The DeYoung Red Diamond is a 5.03-carat unmounted diamond. It is a deep red color, with a slight tint of brown. Red diamonds are the rarest type of colored diamonds. The diamond is a modified round brilliant cut. The facets on the diamond's crown, which resemble kites, are split in two horizontally. This feature makes the DeYoung diamond more brilliant than other diamonds with an ordinary round brilliant cut. The DeYoung Red Diamond is the third-largest red diamond, behind only the 5.05-carat Kazanjian Red Diamond (second-largest) and the 5.11-carat Moussaieff Red Diamond (largest). Its clarity grade is VS-2 (Very Slightly Included). The diamond is a Type IIa diamond, meaning that it does not have any chemical impurities. Type IIa diamonds comprise only 1–2% of all naturally occurring diamonds.
Different diamond types react in different ways to diamond enhancement techniques. Different types can coexist within a single stone; natural diamonds are often mixes of Type Ia and Ib, which can be determined by their infrared absorption spectrum.[2]
This view of diamonds also carries over to the discussion of synthetic diamonds. While he does not believe they will be as valuable as diamonds mined from the earth, he believes that synthetics are yet another commodity that jewelers can sell for whatever value the marketplace deems their worth, but that consumers are always going to want full disclosure that a diamond they are buying is coming from a lab, rather than mined from the ground
The concern in the industry today is what if, just what if there is a way to synthesise diamonds that are non-detectable from natural diamonds? What if technology uses the ability to make this synthetic diamond and no one knows this is synthetic?"
The Gemological Institute of America characterizes the Princie Diamond as fancy intense pink, natural color, VS2 clarity, Type IIa. The Princie diamond is at this time the largest Golconda-type fancy intense pink diamond ever to be graded at the Gemological Institute of America. The Princie also has the property that when exposed to ultraviolet light it displays bright orangey-red fluorescence. According to the Gemological Institute of America this kind of reaction to ultraviolet light is typical of diamonds of Indian origin. Of more than 7 million diamonds that have gone through the Gemological Institute of America's laboratory, no more than 40 exhibited this phenomenon and the Princie is the largest pink diamond that possesses it.
The Tereshchenko Diamond, sometimes known as the Tereshchenko Blue, is a 42.92 carat diamond of blue colour that is cut in the pear shape. The diamond is rare, belonging to the Type IIb diamond, and believed to originate from India. The Tereshchenko diamond is the second biggest blue diamond in the world. Shaped by Cartier for a private order by the Tereshchenko family, the diamond is in the rare Type IIb diamond.
The Kazanjian Red Diamond is a 5.05-carat emerald-cut red diamond. Red diamonds are the rarest type of colored diamond. The diamond measures on the sides, and in depth. It is the second-largest red diamond ever found, behind only the 5.11-carat Moussaieff Red Diamond.
Diamond is a good electrical insulator, having a resistivity of 100 GΩ·m to 1 EΩ·m (10 to 10 Ω·m). Most natural blue diamonds are an exception and are semiconductors due to substitutional boron impurities replacing carbon atoms. Natural blue or blue-gray diamonds, common for the Argyle diamond mine in Australia, are rich in hydrogen; these diamonds are not semiconductors and it is unclear whether hydrogen is actually responsible for their blue-gray color. Natural blue diamonds containing boron and synthetic diamonds doped with boron are p-type semiconductors. N-type diamond films are reproducibly synthesized by phosphorus doping during chemical vapor deposition. Diode p-n junctions and UV light emitting diodes (LEDs, at 235 nm) have been produced by sequential deposition of p-type (boron-doped) and n-type (phosphorus-doped) layers.
Also in 1999, Novatek, a Provo, UT manufacturer of industrial diamonds known for its advancements in diamond synthesis, accidentally discovered that the color of diamonds could be changed by the HPHT process. The company formed NovaDiamond, Inc. to market the process. By applying heat and pressure to natural stones, NovaDiamond could turn brown Type I diamonds light yellow, greenish yellow, or yellowish green; improve Type IIa diamonds by several color grades, even to white; intensify the color of yellow Type I diamonds; and make some bluish gray Type I and Type IIb colorless (although in some cases natural bluish gray diamonds are more valuable left alone, as blue is a highly desired hue). In 2001, however, NovaDiamond quit the HPHT gem business because of what the company's leader, David Hall, characterized as the underhanded practices of dealers. Apparently, dealers were passing off NovaDiamond enhanced gems as naturally colored, and the company refused to be party to this deception.
Type II diamonds have no measurable nitrogen impurities. Type II diamonds absorb in a different region of the infrared, and transmit in the ultraviolet below , unlike Type I diamonds. They also have differing fluorescence characteristics, but no discernible visible absorption spectrum. Type IIa diamond can be colored "pink", "red", or "brown" due to structural anomalies arising through "plastic deformation" during crystal growth—these diamonds are rare (1.8% of gem diamonds), but constitute a large percentage of Australian production. Type IIb diamonds, which account for 0.1% of gem diamonds, are usually light "blue" due to scattered boron within the crystal matrix; these diamonds are also semiconductors, unlike other diamond types (see Electrical properties of diamond). However, a blue-grey color may also occur in Type Ia diamonds and be unrelated to boron. Also not restricted to type are "green" diamonds, whose color is caused by GR1 color centers in the crystal lattice produced by exposure to varying quantities of radiation.
While the gems of the Napoleon Diamond Necklace have never been professionally graded by a lapidary (as they have never been removed from their mountings), infrared spectroscopic analysis of the diamonds has shown that they are primarily Type Ia. However, 13 of the 52 largest diamonds in the necklace are of the rare Type IIa variety. A number of the Type Ia diamonds show indications of sulfide crystal imperfections.
According to their manufacturing methods or bond types, diamond tools can be categorized to the following way:If categorized by use, there are diamond grinding tools, diamond cutting tools (e.g., diamond coated twist drill bits), diamond drilling tools, diamond sawing tools (e.g., diamond saw blades), diamond drawing dies, etc.
Type I diamonds have nitrogen atoms as the main impurity, commonly at a concentration of 0.1%. If the nitrogen atoms are in pairs they do not affect the diamond's color; these are Type IaA. If the nitrogen atoms are in large even-numbered aggregates they impart a yellow to brown tint (Type IaB). About 98% of gem diamonds are type Ia, and most of these are a mixture of IaA and IaB material: these diamonds belong to the "Cape series", named after the diamond-rich region formerly known as Cape Province in North Africa, whose deposits are largely Type Ia. If the nitrogen atoms are dispersed throughout the crystal in isolated sites (not paired or grouped), they give the stone an intense "yellow" or occasionally "brown" tint (Type Ib); the rare "canary" diamonds belong to this type, which represents only 10% of known natural diamonds. Synthetic diamond containing nitrogen is Type Ib. Type I diamonds absorb in both the infrared and ultraviolet region, from . They also have a characteristic fluorescence and visible absorption spectrum (see Optical properties of diamond).
More than 20 other minerals have higher dispersion (that is difference in refractive index for blue and red light) than diamond, such as titanite 0.051, andradite 0.057, cassiterite 0.071, strontium titanate 0.109, sphalerite 0.156, synthetic rutile 0.330, cinnabar 0.4, etc. (see dispersion). However, the combination of dispersion with extreme hardness, wear and chemical resistivity, as well as clever marketing, determines the exceptional value of diamond as a gemstone.
Diamonds exhibit fluorescence, that is, they emit light of various colors and intensities under long-wave ultraviolet light (365 nm): Cape series stones (type Ia) usually fluoresce blue, and these stones may also phosphoresce yellow, a unique property among gemstones. Other possible long-wave fluorescence colors are green (usually in brown stones), yellow, mauve, or red (in type IIb diamonds). In natural diamonds, there is typically little if any response to short-wave ultraviolet, but the reverse is true of synthetic diamonds. Some natural type IIb diamonds phosphoresce blue after exposure to short-wave ultraviolet. In natural diamonds, fluorescence under X-rays is generally bluish-white, yellowish or greenish. Some diamonds, particularly Canadian diamonds, show no fluorescence.
The origin of the luminescence colors is often unclear and not unique. Blue emission from type IIa and IIb diamonds is reliably identified with dislocations by directly correlating the emission with dislocations in an electron microscope. However, blue emission in type Ia diamond could be either due to dislocations or the N3 defects (three nitrogen atoms bordering a vacancy). Green emission in natural diamond is usually due to the H3 center (two substitutional nitrogen atoms separated by a vacancy), whereas in synthetic diamond it usually originates from nickel used as a catalyst (see figure). Orange or red emission could be due to various reasons, one being the nitrogen-vacancy center which is present in sufficient quantities in all types of diamond, even type IIb.