294:); as little as 1 ppm of boron is enough for this effect. However, a blue-grey color may also occur in Type Ia diamonds and be unrelated to boron. Type IIb diamonds show distinctive infrared absorption spectrum and show gradually increasing absorption towards the red side of visible spectrum.
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make up about 0.1% of all natural diamonds. They contain up to 0.05% (500 ppm) of nitrogen, but the impurities are more diffuse: the atoms are dispersed throughout the crystal in isolated sites. Type Ib diamonds absorb green light in addition to blue, and have a more intense or darker
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to long-wave ultraviolet radiation due to the N3 nitrogen centers (the N3 centers do not impair visible color, but are always accompanied by the N2 centers which do). Brown, green, or yellow diamonds show a band in the green at 504 nm (H3 center), sometimes accompanied by two additional weak
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impurities. The absorption spectrum of boron causes these gems to absorb red, orange, and yellow light, lending Type IIb diamonds a light blue or grey color, though examples with low levels of boron impurities can also be colorless. These diamonds are also
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diamonds make up about 0.1% of all natural diamonds, making them one of the rarest natural diamonds and very valuable. In addition to having very low levels of nitrogen impurities comparable to Type IIa diamonds, Type IIb diamonds contain significant
138:, whose deposits are largely Type Ia. Type Ia diamonds often show sharp absorption bands with the main band at 415.5 nm (N3) and weaker lines at 478 nm (N2), 465 nm, 452 nm, 435 nm, and 423 nm (the "Cape lines"), caused by the
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below 225 nm, unlike Type I diamonds. They also have differing fluorescence characteristics. The crystals as found tend to be large and irregular in shape. Type II diamonds were formed under extremely high pressure for longer time periods.
222:. They are very transparent in ultraviolet, down to 230 nm. Occasionally, while Type IIa diamonds are being extruded towards the surface of the Earth, the pressure and tension can cause structural anomalies arising through
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by the level and type of their chemical impurities. Diamonds are separated into five types: Type IaA, Type IaB, Type Ib, Type IIa, and Type IIb. The impurities measured are at the atomic level within the
234:. These imperfections can confer a yellow, brown, orange, pink, red, or purple colour to the gem. Type IIa diamonds can have their structural deformations "repaired" via a high-pressure, high-temperature (
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diamonds make up 1–2% of all natural diamonds (1.8% of gem diamonds). These diamonds are almost or entirely devoid of impurities, and consequently are usually colourless and have the highest
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diamonds make up about 95% of all natural diamonds. The nitrogen impurities, up to 0.3% (3000 ppm), are clustered within the carbon lattice, and are relatively widespread. The
238:) process, removing much or all of the diamond's color. Type IIa diamonds constitute a great percentage of Australian production. Many famous large diamonds, like the
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diamonds belong to this type, which represents only 0.1% of known natural diamonds. The visible absorption spectrum is gradual, without sharp absorption bands.
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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
126:, making it appear pale yellow or almost colorless. Most Ia diamonds are a mixture of IaA and IaB material; these diamonds belong to the
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diamonds have no measurable nitrogen impurities. Type II diamonds absorb in a different region of the infrared, and transmit in the
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471:
428:
Sa, E. S. De (1977). "Uniaxial Stress
Studies of the 2.498 eV (H4), 2.417 eV and 2.536 eV Vibronic Bands in Diamond".
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atoms as their main impurity, commonly at a concentration of 0.1%. Type I diamonds absorb in both the
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51:
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Collins, A. T.; et al. (2005). "High-temperature annealing of optical centers in type-I diamond".
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bands at 537 nm and 495 nm (H4 center, a large complex presumably involving 4 substitutional
164:, where the nitrogen atoms are in large even-numbered aggregates; these impart a yellow to brown tint.
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of
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yellow or brown colour than Type Ia diamonds. The stones have an intense
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diamonds, whose color is derived from exposure to varying quantities of
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Walker, J. (1979). "Optical absorption and luminescence in diamond".
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region, from 320 nm. They also have a characteristic
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of the nitrogen clusters can cause the diamond to absorb
130:, named after the diamond-rich region formerly known as
536:"Optical characterization of natural Argyle diamonds"
286:, unlike other diamond types, due to uncompensated
57:Different diamond types react in different ways to
8:
472:"Gemworld International, Inc.: Archive News"
534:Iakoubovskii, K; Adriaenssens, G.J (2002).
33:is a method of scientifically classifying
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83:diamonds, the most common class, contain
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308:Most blue-gray diamonds coming from the
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262:typically also belong to this type.
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408:"Optical Properties of Diamonds"
292:Electrical properties of diamond
474:. Gemguide.com. Archived from
356:Reports on Progress in Physics
230:crystal structure, leading to
1:
563:10.1016/S0925-9635(01)00533-7
543:Diamond and Related Materials
105:Optical properties of diamond
27:Diamond classification system
386:10.1088/0034-4885/42/10/001
297:Not restricted to type are
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151:and 2 lattice vacancies).
140:N2 and N3 nitrogen centers
258:diamonds grown using the
226:during the growth of the
504:(8): 083517–083517–10.
410:. Allaboutgemstones.com
450:10.1098/rspa.1977.0165
314:defects and impurities
142:. They also show blue
65:absorption spectrum.
52:infrared spectrometer
46:atoms and so, unlike
220:thermal conductivity
555:2002DRM....11..125I
510:2005JAP....97h3517C
442:1977RSPSA.357..231S
368:1979RPPh...42.1605W
254:are Type IIa.
224:plastic deformation
120:absorption spectrum
101:absorption spectrum
59:diamond enhancement
303:ionizing radiation
518:10.1063/1.1866501
362:(10): 1605–1659.
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331:List of diamonds
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284:semiconductors
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252:The Lulo Rose
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232:imperfections
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162:Type IaB
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132:Cape Province
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200:Type II
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195:Type II
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174:Type Ib
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169:Type Ib
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144:fluorescence
136:South Africa
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116:Type Ia
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111:Type Ia
99:and visible
97:fluorescence
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31:Diamond type
30:
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310:Argyle mine
260:CVD process
228:tetrahedral
204:ultraviolet
128:Cape series
93:ultraviolet
81:Type I
76:Type I
54:to detect.
482:2010-03-19
414:2010-03-19
337:References
244:Koh-i-Noor
124:blue light
48:inclusions
394:250857323
372:CiteSeerX
256:Synthetic
576:Category
458:98842822
320:See also
240:Cullinan
89:infrared
85:nitrogen
63:infrared
35:diamonds
582:Diamond
551:Bibcode
549:: 125.
506:Bibcode
438:Bibcode
364:Bibcode
456:
392:
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281:p-type
250:, and
189:canary
179:yellow
44:carbon
539:(PDF)
454:S2CID
390:S2CID
299:green
290:(see
276:boron
184:brown
103:(see
236:HPHT
91:and
559:doi
514:doi
446:doi
434:357
382:doi
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42:of
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