Beryl is a mineral with the chemical composition Be3Al2(Si6O18) that commonly occurs in silica-rich granites and pegmatites. It has a hexagonal crystal structure and comes in several varieties distinguished by color, including aquamarine (pale blue-green), emerald (intense green), heliodor (pale yellow-orange), morganite (pale pink), goshenite (colorless), and the rare red bixbite variety. Beryl has physical properties of hardness 7.5-8, specific gravity 2.6-2.9, and indistinct cleavage. Its optical properties include refractive index 1.56-1.604

1. BERYL
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2. Introduction
• Chemical composition of Beryl is Be3Al2(Si6O18)
• It is a relatively common mineral although it does contain the rare element
beryllium
• Beryl is a single mineral with many varieties that are distinguished by their
color
• Those are;
Pale green to blue- Aquamarine
Intense green- Emerald
Pale yellow to yellowish-orange- Heliodor
 Pale pink - Morganite
 Colorless beryl variety - Goshenite
 Very rare red gem beryl variety - Bixbite
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3. Beryl Occurrence
• Beryl occurs most often in silica rich granites and granite pegmatites
in association with quartz, feldspars and muscovite
Eg: aquamarine
heliodor occurred as granite pegmatites
morganite
• Beryl also occurs in mica schists of metamorphic-hydrothermal
deposits
Eg: emerald
• It is often found in eluvial and aluvial deposits.
• The rare red beryl variety known as bixbite occurs within gas cavities
in rhyolite
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4. Diagnostic Features
• Beryl is usually recognized by its;
Hexagonal form
 Color
• Distinguished from quartz by its higher specific gravity and from
apatite by its greater hardness.
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5. Physical Properties of Beryl
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• Mohs Hardness-7.5 to 8
• Specific Gravity-2.60 to 2.90
• Cleavage Quality-Indistinct
• Fracture-Uneven,Conchoidal

6. Optical Properties of Beryl
• Refractive Index-1.560 to 1.604
• Optical Character-Uniaxial/-
• Birefringence-0.003 to 0.010
• Pleochroism-Red beryl - distinct: (orangy)-red - purplish-red; Golden
beryl - weak: yellowish - greenish-yellow; Green beryl - distinct:
yellow-green - blue-green
• Dispersion-0.014
• Chatoyancy- “star” may show brownish to black body color,
"colorless" when viewed from the side
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7. Colour
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• Colour (General)- Colourless, green, blue, yellow, yellow-green,
pink, red
• Causes of Colour-
Dark blue CO3 and NO3 color centers due to irradiation.
Light blue (aquamarine) Fe2+ in the channels of the structure.
Darker blue (aquamarine) Fe2+O-Fe3+ intervalence charge transfer.
Green yellow + blue O2→Fe2+ charge transfer and Fe2+in the
channels.
Green (emerald, mint beryl) Cr3+ and/or V3+ in octahedral
coordination.
Red Mn3+in octahedral coordination.
Pink (morganite) Mn2+in octahedral coordination

8. Colour cnt.
• Transparency Transparent,Translucent
• Lustre Vitreous
Crystallography of Beryl
• Crystal System Hexagonal
• Habit Prismatic
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9. Varieties
1. Aquamarine
• Aquamarine, named for the Latin phrase "water of the sea", is the
blue to blue-green variety Beryl.
• Aquamarine ranges in color from a faint light blue to blue and bluish-
green, with lighter colored stones being the more common type.
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10. 2. Emerald
• Emerald, the green variety of Beryl, is the most famous and valuable
green gemstone.
• Its beautiful green color, combined with durability and rarity, make it
one of the most expensive gemstones.
• Deep green is the most desired color in Emeralds. In general the paler
the color of an Emerald, the lesser its value.
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11. 3. Heliodor
• Heliodor is the greenish-yellow to yellow varieties of Beryl.
• Heliodor has a greenish-yellow hue
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12. 4. Morganite
• Morganite is the pink to purplish-pink variety of Beryl.
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13. 5. Goshenite
• Goshenite is the white to colorless variety of Beryl
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14. 6. Bixbite
• It is also known as red beryl
• Rare, deep red variety of Beryl found only two localities in Utah.
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15. THANK YOU..!!
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K.K.A.D.Kumar
UWU/MRT/13/0018
Mineral Resources and Technology