Last updated

Three varieties of beryl (left to right): morganite, aquamarine and emerald
Category Cyclosilicate
(repeating unit)
IMA symbol Brl [1]
Strunz classification 9.CJ.05
Crystal system Hexagonal
Crystal class Dihexagonal dipyramidal (6/mmm)
H-M symbol: (6/m 2/m 2/m)
Space group P6/mcc
Unit cell a = 9.21  Å, c = 9.19 Å; Z = 2
Formula mass 537.50 g/mol
ColorGreen, blue, yellow, colorless, pink, and others
Crystal habit Prismatic to tabular crystals; radial, columnar; granular to compact massive
Twinning Rare
Cleavage Imperfect on {0001}
Fracture Conchoidal to irregular
Tenacity Brittle
Mohs scale hardness7.5 – 8
Luster Vitreous to resinous
Streak White
Diaphaneity Transparent to translucent
Specific gravity 2.63 - 2.92
Optical propertiesUniaxial (-)
Refractive index nω = 1.564–1.595
nε = 1.568–1.602
Birefringence δ = 0.0040–0.0070
Pleochroism Weak to distinct
Ultraviolet fluorescence None (some fracture filling materials used to improve emerald's clarity do fluoresce, but the stone itself does not). Morganite has weak violet fluorescence.
References [2] [3] [4] [5] : 112

Beryl ( /ˈbɛrəl/ BERR-əl) is a mineral composed of beryllium aluminium silicate with the chemical formula Be3Al2Si6O18. [6] Well-known varieties of beryl include emerald and aquamarine. Naturally occurring, hexagonal crystals of beryl can be up to several meters in size, but terminated crystals are relatively rare. Pure beryl is colorless, but it is frequently tinted by impurities; possible colors are green, blue, yellow, pink, and red (the rarest). It is an ore source of beryllium. [7]


Main beryl producing countries Beryl.jpg
Main beryl producing countries


The word berylMiddle English : beril – is borrowed, via Old French : beryl and Latin : beryllus, from Ancient Greek βήρυλλος bḗryllos, which referred to a 'precious blue-green color-of-sea-water stone'; [2] from Prakrit veruḷiya, veḷuriya 'beryl' (compare the pseudo-Sanskritization वैडूर्य vaiḍūrya 'cat's eye; jewel; lapis lazuli', traditionally explained as '(brought) from (the city of) Vidūra'), [8] which is ultimately of Dravidian origin, maybe from the name of Belur or Velur, a town in Karnataka, southern India. [9] The term was later adopted for the mineral beryl more exclusively.

When the first eyeglasses were constructed in 13th-century Italy, the lenses were made of beryl (or of rock crystal) as glass could not be made clear enough. Consequently, glasses were named Brillen in German [10] (bril in Dutch and briller in Danish).


Beryl is a common mineral, and it is widely distributed in nature. It found most commonly in granitic pegmatites, but also occurs in mica schists, such as those of the Ural Mountains, and in limestone in Colombia. [11] It is less common in ordinary granite and is only infrequently found in nepheline syenite. Beryl is often associated with tin and tungsten ore bodies formed as high-temperature hydrothermal veins. In granitic pegmatites, beryl is found in association with quartz, potassium feldspar, albite, muscovite, biotite, and tourmaline. Beryl is sometimes found in metasomatic contacts of igneous intrusions with gneiss, schist, or carbonate rocks. [12] Common beryl, mined as beryllium ore, is found in small deposits in many countries, but the main producers are Russia, Brazil, and the United States. [11]

New England's pegmatites have produced some of the largest beryls found, including one massive crystal from the Bumpus Quarry in Albany, Maine with dimensions 5.5 by 1.2 m (18.0 by 3.9 ft) with a mass of around 18 metric tons; it is New Hampshire's state mineral. As of 1999, the world's largest known naturally occurring crystal of any mineral is a crystal of beryl from Malakialina, Madagascar, 18 m (59 ft) long and 3.5 m (11 ft) in diameter, and weighing 380,000 kg (840,000 lb). [13]

Crystal habit and structure

Beryl crystal structure with view down C axis Beryl Crystal Structure.png
Beryl crystal structure with view down C axis

Beryl belongs to the hexagonal crystal system. Normally beryl forms hexagonal columns but can also occur in massive habits. As a cyclosilicate beryl incorporates rings of silicate tetrahedra of Si6O18 that are arranged in columns along the C axis and as parallel layers perpendicular to the C axis, forming channels along the C axis. [7] These channels permit a variety of ions, neutral atoms, and molecules to be incorporated into the crystal thus disrupting the overall charge of the crystal permitting further substitutions in aluminium, silicon, and beryllium sites in the crystal structure. [7] These impurities give rise to the variety of colors of beryl that can be found. Increasing alkali content within the silicate ring channels causes increases to the refractive indices and birefringence. [14]

Human health impact

Beryl is a beryllium compound that is a known carcinogen with acute toxic effects leading to pneumonitis when inhaled. [15] Care must thus be used when mining, handling, and refining these gems.


Aquamarine and maxixe

Aquamarine Beryl-209736.jpg

Aquamarine (from Latin : aqua marina, "sea water" [16] ) is a blue or cyan variety of beryl. It occurs at most localities which yield ordinary beryl. The gem-gravel placer deposits of Sri Lanka contain aquamarine. Green-yellow beryl, such as that occurring in Brazil, is sometimes called chrysolite aquamarine. [17] The deep blue version of aquamarine is called maxixe. [18]

Faceted aquamarine Aquamarin cut.jpg
Faceted aquamarine

The pale blue color of aquamarine is attributed to Fe2+. Fe3+ ions produce golden-yellow color, and when both Fe2+ and Fe3+ are present, the color is a darker blue as in maxixe. [19] [20] Decoloration of maxixe by light or heat thus may be due to the charge transfer between Fe3+ and Fe2+. [21]

In the United States, aquamarines can be found at the summit of Mt. Antero in the Sawatch Range in central Colorado, and in the New England and North Carolina pegmatites. [22] Aquamarines are also present in the state of Wyoming, aquamarine has been discovered in the Big Horn Mountains, near Powder River Pass. [23] Another location within the United States is the Sawtooth Range near Stanley, Idaho, although the minerals are within a wilderness area which prevents collecting. [24] In Brazil, there are mines in the states of Minas Gerais, [22] Espírito Santo, and Bahia, and minorly in Rio Grande do Norte. [25] The mines of Colombia, Madagascar, Russia, [22] Namibia, [26] Zambia, [27] Malawi, Tanzania, and Kenya [28] also produce aquamarine.


Rough emerald on matrix Beryl var. emeraude sur gangue (Muzo Mine Boyaca - Colombie) 15.jpg
Rough emerald on matrix

Emerald is green beryl, colored by around 2% chromium and sometimes vanadium. [29] [30] Most emeralds are highly included, so their brittleness (resistance to breakage) is classified as generally poor., [31]

The modern English word "emerald" comes via Middle English emeraude, imported from modern French via Old French ésmeraude and Medieval Latin esmaraldus, from Latin smaragdus, from Greek σμάραγδος smaragdos meaning ‘green gem’, from Hebrew ברקת bareket (one of the twelve stones in the Hoshen pectoral pendant of the Kohen HaGadol), meaning ‘lightning flash’, referring to ‘emerald’, relating to Akkadian baraqtu, meaning ‘emerald’, and possibly relating to the Sanskrit word मरकत marakata, meaning ‘green’. [32] The Semitic word אזמרגד izmargad, meaning ‘emerald’, is a back-loan, deriving from Greek smaragdos.

Faceted emerald, 1.07ct, Colombia Smaragd-G-EmpireTheWorldOfGems.jpg
Faceted emerald, 1.07ct, Colombia

Emeralds in antiquity were mined by the Egyptians and in what is now Austria, as well as Swat in contemporary Pakistan. [33] A rare type of emerald known as a trapiche emerald is occasionally found in the mines of Colombia. A trapiche emerald exhibits a "star" pattern; it has raylike spokes of dark carbon impurities that give the emerald a six-pointed radial pattern. It is named for the trapiche , a grinding wheel used to process sugarcane in the region. Colombian emeralds are generally the most prized due to their transparency and fire. Some of the rarest emeralds come from the two main emerald belts in the Eastern Ranges of the Colombian Andes: Muzo and Coscuez west of the Altiplano Cundiboyacense, and Chivor and Somondoco to the east. Fine emeralds are also found in other countries, such as Zambia, Brazil, Zimbabwe, Madagascar, Pakistan, India, Afghanistan and Russia. In the US, emeralds can be found in Hiddenite, North Carolina. In 1998, emeralds were discovered in Yukon.

Emerald is a rare and valuable gemstone and, as such, it has provided the incentive for developing synthetic emeralds. Both hydrothermal [34] and flux-growth synthetics have been produced. The first commercially successful emerald synthesis process was that of Carroll Chatham. [35] The other large producer of flux emeralds was Pierre Gilson Sr., which has been on the market since 1964. Gilson's emeralds are usually grown on natural colorless beryl seeds which become coated on both sides. Growth occurs at the rate of 1 millimetre (0.039 in) per month, a typical seven-month growth run producing emerald crystals of 7 mm of thickness. [36] The green color of emeralds is widely attributed to presence of Cr3+ ions. [37] [19] [20] Intensely green beryls from Brazil, Zimbabwe and elsewhere in which the color is attributed to vanadium have also been sold and certified as emeralds. [38] [39] [40]

Golden beryl and heliodor

Faceted golden beryl, 48.75 ct, Brazil Heliodor-G-EmpireTheWorldOfGems.jpg
Faceted golden beryl, 48.75 ct, Brazil

Golden beryl can range in colors from pale yellow to a brilliant gold. Unlike emerald, golden beryl generally has very few flaws. The term "golden beryl" is sometimes synonymous with heliodor (from Greek hēlios – ἥλιος "sun" + dōron – δῶρον "gift") but golden beryl refers to pure yellow or golden yellow shades, while heliodor refers to the greenish-yellow shades. The golden yellow color is attributed to Fe3+ ions. [29] [37] Both golden beryl and heliodor are used as gems. Probably the largest cut golden beryl is the flawless 2054-carat stone on display in the Hall of Gems, Washington, D.C., United States. [41]


Goshenite Goshenite.jpg
Faceted goshenite, 1.88 ct, Brazil Goshenit-G-EmpireTheWorldOfGems.jpg
Faceted goshenite, 1.88 ct, Brazil

Colorless beryl is called goshenite. The name originates from Goshen, Massachusetts, where it was originally discovered. In the past, goshenite was used for manufacturing eyeglasses and lenses owing to its transparency. Nowadays, it is most commonly used for gemstone purposes. [42] [43]

The gem value of goshenite is relatively low. However, goshenite can be colored yellow, green, pink, blue and in intermediate colors by irradiating it with high-energy particles. The resulting color depends on the content of Ca, Sc, Ti, V, Fe, and Co impurities. [37]


Morganite Beryl-Quartz-morganite brazil1.jpg
Faceted morganite, 2.01 ct, Brazil Morganit-G-EmpireTheWorldOfGems.jpg
Faceted morganite, 2.01 ct, Brazil

Morganite, also known as "pink beryl", "rose beryl", "pink emerald" (which is not a legal term according to the new Federal Trade Commission Guidelines and Regulations), and "cesian (or caesian) beryl", is a rare light pink to rose-colored gem-quality variety of beryl. Orange/yellow varieties of morganite can also be found, and color banding is common. It can be routinely heat treated to remove patches of yellow and is occasionally treated by irradiation to improve its color. The pink color of morganite is attributed to Mn2+ ions. [29]

Red beryl

Red beryl Beryl-235618.jpg
Red beryl

Red variety of beryl (the "bixbite") was first described in 1904 for an occurrence, its type locality, at Maynard's Claim (Pismire Knolls), Thomas Range, Juab County, Utah. [44] [45] The dark red color is attributed to Mn3+ ions. [29] Old synonym "bixbite" is deprecated from the CIBJO because of the possibility of confusion with the mineral bixbyite (both named after mineralogist Maynard Bixby). [46] Red "bixbite" beryl formerly was marketed as "red" or "scarlet emerald", but these terms involving "Emerald" terminology are now prohibited in the US. [47]

Faceted red beryl, 0.56 ct, Utah, US RedBeryl-G-EmpireTheWorldOfGems.jpg
Faceted red beryl, 0.56 ct, Utah, US

Red beryl is very rare and has only been reported from a handful of North American locations: Wah Wah Mountains, Beaver County, Utah; Paramount Canyon, Round Mountain, Juab County, Utah; and Sierra County, New Mexico, although this locality does not often produce gem-grade stones. [44] The bulk of gem-grade red beryl comes from the Ruby-Violet Claim in the Wah Wah Mts. of midwestern Utah, discovered in 1958 by Lamar Hodges, of Fillmore, Utah, while he was prospecting for uranium. [48] Red beryl has been known to be confused with pezzottaite, a caesium analog of beryl, found in Madagascar and, more recently, Afghanistan; cut gems of the two varieties can be distinguished by their difference in refractive index, and the rough crystals easily by their differing crystal systems (pezzottaite trigonal, red beryl hexagonal). Synthetic red beryl is also produced. [49] Like emerald and unlike most other varieties of beryl, the red ones are usually highly included.

While gem beryls are ordinarily found in pegmatites and certain metamorphic stones, red beryl occurs in topaz-bearing rhyolites. [50] It is formed by crystallizing under low pressure and high temperature from a pneumatolytic phase along fractures or within near-surface miarolitic cavities of the rhyolite. Associated minerals include bixbyite, quartz, orthoclase, topaz, spessartine, pseudobrookite and hematite. [45]

See also

Related Research Articles

<span class="mw-page-title-main">Gemstone</span> Piece of mineral crystal used to make jewelry

A gemstone is a piece of mineral crystal which, in cut and polished form, is used to make jewelry or other adornments. However, certain rocks and occasionally organic materials that are not minerals are also used for jewelry and are therefore often considered to be gemstones as well. Most gemstones are hard, but some soft minerals are used in jewelry because of their luster or other physical properties that have aesthetic value. Rarity and notoriety are other characteristics that lend value to gemstones.

<span class="mw-page-title-main">Spinel</span> Mineral or gemstone

Spinel is the magnesium/aluminium member of the larger spinel group of minerals. It has the formula MgAl
in the cubic crystal system. Its name comes from the Latin word spinella, which means spine in reference to its pointed crystals.

<span class="mw-page-title-main">Sapphire</span> Gem variety of corundum

Sapphire is a precious gemstone, a variety of the mineral corundum, consisting of aluminium oxide (α-Al2O3) with trace amounts of elements such as iron, titanium, chromium, vanadium, or magnesium. The name sapphire is derived via the Latin "sapphirus" from the Greek "sappheiros", which referred to lapis lazuli. It is typically blue, but natural "fancy" sapphires also occur in yellow, purple, orange, and green colors; "parti sapphires" show two or more colors. Red corundum stones also occur, but are called rubies rather than sapphires. Pink-colored corundum may be classified either as ruby or sapphire depending on locale. Commonly, natural sapphires are cut and polished into gemstones and worn in jewelry. They also may be created synthetically in laboratories for industrial or decorative purposes in large crystal boules. Because of the remarkable hardness of sapphires – 9 on the Mohs scale (the third hardest mineral, after diamond at 10 and moissanite at 9.5) – sapphires are also used in some non-ornamental applications, such as infrared optical components, high-durability windows, wristwatch crystals and movement bearings, and very thin electronic wafers, which are used as the insulating substrates of special-purpose solid-state electronics such as integrated circuits and GaN-based blue LEDs. Sapphire is the birthstone for September and the gem of the 45th anniversary. A sapphire jubilee occurs after 65 years.

<span class="mw-page-title-main">Topaz</span> Silicate mineral

Topaz is a silicate mineral of aluminium and fluorine with the chemical formula Al2SiO4(F,OH)2. It is used as a gemstone in jewelry and other adornments. Common topaz in its natural state is colorless, though trace element impurities can make it pale blue or golden brown to yellow orange. Topaz is often treated with heat or radiation to make it a deep blue, reddish-orange, pale green, pink, or purple.

<span class="mw-page-title-main">Tourmaline</span> Cyclosilicate mineral group

Tourmaline is a crystalline silicate mineral group in which boron is compounded with elements such as aluminium, iron, magnesium, sodium, lithium, or potassium. Tourmaline is a gemstone and can be found in a wide variety of colors.

<span class="mw-page-title-main">Garnet</span> Mineral, semi-precious stone

Garnets are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives.

<span class="mw-page-title-main">Pegmatite</span> Igneous rock with very large interlocked crystals

A pegmatite is an igneous rock showing a very coarse texture, with large interlocking crystals usually greater in size than 1 cm (0.4 in) and sometimes greater than 1 meter (3 ft). Most pegmatites are composed of quartz, feldspar, and mica, having a similar silicic composition to granite. However, rarer intermediate composition and mafic pegmatites are known.

<span class="mw-page-title-main">Peridot</span> Green gem-quality mineral

Peridot, sometimes called chrysolite, is a deep yellowish-green transparent variety of olivine. Peridot is one of the few gemstones that occurs in only one color.

<span class="mw-page-title-main">Chrysoberyl</span> Mineral or gemstone of beryllium aluminate

The mineral or gemstone chrysoberyl is an aluminate of beryllium with the formula BeAl2O4. The name chrysoberyl is derived from the Greek words χρυσός chrysos and βήρυλλος beryllos, meaning "a gold-white spar". Despite the similarity of their names, chrysoberyl and beryl are two completely different gemstones, although they both contain beryllium. Chrysoberyl is the third-hardest frequently encountered natural gemstone and lies at 8.5 on the Mohs scale of mineral hardness, between corundum (9) and topaz (8).

<span class="mw-page-title-main">Pleochroism</span> Optical phenomenon

Pleochroism is an optical phenomenon in which a substance has different colors when observed at different angles, especially with polarized light.

<span class="mw-page-title-main">Spodumene</span> Pyroxene, single chain inosilicate mineral

Spodumene is a pyroxene mineral consisting of lithium aluminium inosilicate, LiAl(SiO3)2, and is a source of lithium. It occurs as colorless to yellowish, purplish, or lilac kunzite (see below), yellowish-green or emerald-green hiddenite, prismatic crystals, often of great size. Single crystals of 14.3 m (47 ft) in size are reported from the Black Hills of South Dakota, United States.

<span class="mw-page-title-main">Brazilianite</span>

Brazilianite, whose name derives from its country of origin, Brazil, is a typically yellow-green phosphate mineral, most commonly found in phosphate-rich pegmatites.

<span class="mw-page-title-main">Priestly breastplate</span> Jewish ritual object worn by the High Priest

The priestly breastplate or breastpiece of judgment was a sacred breastplate worn by the High Priest of the Israelites, according to the Book of Exodus. In the biblical account, the breastplate is termed the breastplate of judgment, because the Urim and Thummim were placed upon it.(Exodus 28:30). These elements of the breastplate are said in the Exodus verse to carry the judgement of God concerning the Israelites at all times.

<span class="mw-page-title-main">Phenakite</span>

Phenakite or phenacite is a fairly rare nesosilicate mineral consisting of beryllium orthosilicate, Be2SiO4. Occasionally used as a gemstone, phenakite occurs as isolated crystals, which are rhombohedral with parallel-faced hemihedrism, and are either lenticular or prismatic in habit: the lenticular habit is determined by the development of faces of several obtuse rhombohedra and the absence of prism faces. There is no cleavage, and the fracture is conchoidal. The Mohs hardness is high, being 7.5 – 8; the specific gravity is 2.96. The crystals are sometimes perfectly colorless and transparent, but more often they are greyish or yellowish and only translucent; occasionally they are pale rose-red. In general appearance the mineral is not unlike quartz, for which indeed it has been mistaken. Its name comes from Ancient Greek: φέναξ, romanized: phénax, meaning "deceiver" due to its close visual similarity to quartz, named by Nils Gustaf Nordenskiöld in 1833.

<span class="mw-page-title-main">Pezzottaite</span> Mineral species

Pezzottaite, marketed under the name raspberyl or raspberry beryl, is a mineral species first recognized by the International Mineralogical Association in September 2003. Pezzottaite is a caesium analogue of beryl, a silicate of caesium, beryllium, lithium and aluminium, with the chemical formula Cs(Be2Li)Al2Si6O18. Named after Italian geologist and mineralogist Federico Pezzotta, pezzottaite was first thought to be either red beryl or a new variety of beryl ("caesium beryl"); unlike actual beryl, however, pezzottaite contains lithium and crystallizes in the trigonal crystal system rather than the hexagonal system.

<span class="mw-page-title-main">Goshenite (gem)</span> Variety of beryl

Goshenite is a colorless gem variety of beryl. It is called the mother of all gemstones because it can be transformed into other like emerald, morganite, or bixbite. Goshenite is also referred to as the purest form of beryl since there are generally no other elements present in the stone. The gem is used as imitation for diamond or emerald by adding colored foil on it.

<span class="mw-page-title-main">Morganite (gem)</span> Beryl variety

Morganite is an orange or pink variety of beryl and is also a gemstone. Morganite is mined in Brazil, Afghanistan, Mozambique, Namibia, the United States, and Madagascar.

<span class="mw-page-title-main">Red beryl</span> Rare variety of beryl

Red beryl, formerly known as bixbite and marketed as red emerald or scarlet emerald, is an extremely rare variety of beryl as well as one of the rarest minerals on Earth. The gem gets its red color from manganese ions embedded inside of beryllium aluminium cyclosilicate crystals. The color of red beryl is stable up to 1,000 °C (1,830 °F). Red Beryl can come in various tints like strawberry, bright ruby, cherry, and orange.

<span class="mw-page-title-main">Aquamarine (gem)</span> Variety of beryl

Aquamarine is a pale-blue to light-green variety of beryl. The color of aquamarine can be changed by heat.


  1. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi: 10.1180/mgm.2021.43 . S2CID   235729616.
  2. 1 2 "Beryl". Archived from the original on 26 October 2007.
  3. "Beryl Mineral Data". Archived from the original on 12 May 2008.
  4. "Beryl" (PDF). Mineral Data Publishing. 2001. Archived (PDF) from the original on 28 November 2011.
  5. Schumann, Walter (2009). Gemstones of the World. Sterling Publishing Co. ISBN   978-1-402-76829-3. Archived from the original on 20 November 2017. Retrieved 22 May 2018.
  6. "Beryl". Retrieved 12 July 2018.
  7. 1 2 3 Klein, Cornelis; Dutrow, Barbara; Dana, James Dwight (2007). The Manual of Mineral Science : (after James D. Dana) (23rd ed.). Hoboken, N.J.: J. Wiley. ISBN   978-0-471-72157-4. OCLC   76798190.
  8. Walter W. Skeat; Walter William Skeat (1993). The Concise Dictionary of English Etymology. Wordsworth Editions. p. 36. ISBN   978-1-85326-311-8.
  9. "beryl". Merriam-Webster . Archived from the original on 9 October 2013. Retrieved 27 January 2014.
  10. Kluge, Alexander, ed. (1975). "Brillen". Etymologisches Wörterbuch der deutschen Sprache (21 ed.).
  11. 1 2 Klein, Cornelis; Hurlbut, Cornelius S. Jr. (1993). Manual of mineralogy : (after James D. Dana) (21st ed.). New York: Wiley. p. 472. ISBN   047157452X.
  12. Nesse, William D. (2000). Introduction to mineralogy. New York: Oxford University Press. p. 301. ISBN   9780195106916.
  13. G. Cressey and I. F. Mercer, (1999) Crystals, London, Natural History Museum, page 58
  14. Deer, W.A.; Howie, R.A.; Zussman, J. (2013). An introduction to the rock-forming minerals (Third ed.). London, UK. ISBN   978-0-903-05627-4. OCLC   858884283.
  15. "Concise International Chemical Assessment Document 32, Beryllium and Beryllium compounds" . Retrieved 16 July 2019.
  16. "aquamarine". Merriam-Webster . Archived from the original on 6 February 2017. Retrieved 5 February 2017.
  17. Owens, George (1957). "The Amateur Lapidary". Rocks & Minerals. 32 (9–10): 471. doi:10.1080/00357529.1957.11766963.
  18. Grande, Lance; Augustyn, Allison (November 15, 2009). Gems and Gemstones: Timeless Natural Beauty of the Mineral World. University of Chicago Press. p. 125. ISBN   978-0-226-30511-0.
  19. 1 2 Viana, R.R.; da Costa, G.M.; de Grave, E.; Stern, W.B.; Jordt-Evangelista, H. (2002). "Characterization of beryl (aquamarine variety) by Mössbauer spectroscopy". Physics and Chemistry of Minerals. 29 (1): 78. Bibcode:2002PCM....29...78V. doi:10.1007/s002690100210. S2CID   96286267.
  20. 1 2 Blak, Ana Regina; Isotani, Sadao; Watanabe, Shigueo (1983). "Optical absorption and electron spin resonance in blue and green natural beryl: A reply". Physics and Chemistry of Minerals. 9 (6): 279. Bibcode:1983PCM.....9..279B. doi:10.1007/BF00309581. S2CID   97353580.
  21. Andersson, Lars Olov (July 15, 2019). "Comments on Beryl Colors and on Other Observations Regarding Iron-containing Beryls". The Canadian Mineralogist. 57 (4): 551–566. doi:10.3749/canmin.1900021. S2CID   200066862.
  22. 1 2 3 Sinkankas, John (1964). Mineralogy for amateurs. Princeton, N.J.: Van Nostrand. pp. 507–509. ISBN   0442276249.
  23. Fritsch, E.; Shigley, J.E. (1989). "Contribution to the identification of treated colored diamonds: diamonds with peculiar color-zoned pavilions". The Quarterly Journal of the Gemological Institute of America. 25 (2): 95–101.
  24. Kiilsgaard, T.H.; Freeman, V.L.; Coffman, J.S. (1970). "Mineral resources of the Sawtooth Primitive Area, Idaho". U.S. Geological Survey Bulletin. 1319-D: D-108. doi: 10.3133/b1319D .
  25. Cassedanne, J.; Philippo, Simon (2015). Minerals and Gem deposits of the eastern Brazilian pegmatites. Musée national d’histoire naturelle Luxembourg. pp. 139–206. Retrieved April 15, 2022.
  26. Klein & Hurlbut 1993, p. 472.
  27. Carranza, E. J. M.; Woldai, T.; Chikambwe, E. M. (March 2005). "Application of Data-Driven Evidential Belief Functions to Prospectivity Mapping for Aquamarine-Bearing Pegmatites, Lundazi District, Zambia". Natural Resources Research. 14 (1): 47–63. doi:10.1007/s11053-005-4678-9. S2CID   129933245.
  28. Yager, T.R. (2007). Minerals Yearbook. U.S. Geological Survey. pp. 22.1, 27.1, 39.3. Retrieved April 15, 2022.
  29. 1 2 3 4 "Color in the beryl group". Mineral Spectroscopy Server. California Institute of Technology. Archived from the original on 22 August 2011. Retrieved 6 June 2009.
  30. Hurlbut, Cornelius S. Jr & Kammerling, Robert C. (1991). Gemology. New York: John Wiley & Sons. p. 203. ISBN   978-0-471-42224-2.
  31. "Emerald Quality Factors". Gemological Institute of America. Archived from the original on November 2, 2016. Retrieved November 1, 2016.
  32. Fernie M.D., W.T. (1906). Precious Stones for Curative Wear. John Wright. & Co.
  33. Giuliani, G.; Chaussidon, M.; Schubnel, H.J.; Piat, D.H.; Rollion-Bard, C.; France-Lanord, C.; Giard, D.; de Narvaez, D.; Rondeau, B. (2000). "Oxygen isotopes and emerald trade routes since antiquity". Science. 287 (5453): 631–633. Bibcode:2000Sci...287..631G. doi:10.1126/science.287.5453.631. PMID   10649992.
  34. Hosaka, M. (1991). "Hydrothermal growth of gem stones and their characterization". Progress in Crystal Growth and Characterization of Materials. 21 (1–4): 71. doi:10.1016/0960-8974(91)90008-Z.
  35. "Carroll Chatham". The Gemology Project. Archived from the original on 10 September 2011.
  36. Nassau, K. (1980). Gems Made by Man. Gemological Institute of America. ISBN   978-0-873-11016-7.
  37. 1 2 3 Ibragimova, E.M.; Mukhamedshina, N.M.; Islamov, A.Kh. (2009). "Correlations between admixtures and color centers created upon irradiation of natural beryl crystals". Inorganic Materials. 45 (2): 162. doi:10.1134/S0020168509020101. S2CID   96344887.
  38. Thomas, Arthur (2008). Gemstones: Properties, Identification and Use. London: New Holland. pp. 77–78. ISBN   978-1-845-37602-4.
  39. Behmenburg, Christa; Conklin, Lawrence; Giuliani, Gaston; Glas, Maximilian; Gray, Patricia; Gray, Michael (January 2002). Giuliani, Gaston; Jarnot, Miranda; Neumeier, Gunther; Ottaway, Terri; Sinkankas, John (eds.). Emeralds of the World. ExtraLapis. Vol. 2. East Hampton, CT: Lapis International. pp. 75–77. ISBN   978-0-971-53711-8.
  40. Deer, W.A.; Zussman, J.; Howie, R.A. (1997). Disilicates and Ring Silicates. Rock-forming Minerals. Vol. 1B (2 ed.). Bath: Geological Society of London. pp. 393–394. ISBN   978-1-897-79989-5.
  41. Thomas, Arthur (2007). Gemstones. New Holland Publishers. p. 77. ISBN   978-1-845-37602-4 via Google Books.
  42. "Goshenite, the colorless variety of beryl". Amethyst Galleries. Archived from the original on 30 June 2009. Retrieved 6 June 2009.
  43. "Goshenite Gem". Optical 2 March 2009. Archived from the original on 9 July 2009. Retrieved 6 June 2009.
  44. 1 2 "Red Beryl". Archived from the original on 3 December 2013.
  45. 1 2 Ege, Carl (September 2002). "What gemstone is found in Utah that is rarer than diamond and more valuable than gold?". Survey Notes. Vol. 34, no. 3. Archived from the original on 8 November 2010. Retrieved 2 July 2011.
  46. "The Mineral Beryl". Archived from the original on 28 August 2017. Retrieved 28 August 2017.
  47. 16 CFR 23.26
  48. "Red Emerald History". Archived from the original on 3 December 2007. Retrieved 21 November 2007.
  49. "Bixbite". The Gemstone List. Archived from the original on 12 March 2016.
  50. "Red beryl value, price, and jewelry information". International Gem Society. Archived from the original on 28 August 2017. Retrieved 28 August 2017.

Further reading