Beryl from Brazilia:
Varieties of Beryl are emerald and aquamarine.
Pure Beryl is colorless.
Impirities gives the color of green, blue, yellow, red (rarest) and white.
Beryl is a source of beryllium.
The first eyeglasses where constructed in 13th century in Italy, lanses made of beryl.
Can contain sodium, lithium and cesium. Variable formula (Be,Na,Li,Ce)Al2Si6O18
Health:
Beryl has beryllium and is known to be cancinogen with acute toxic effects leading to pneumonitis when inhaled.
Characteristics:
Category: cyclosilicate
Formula: Be3Al2Si6O18
Beryllium 5,03%; Aluminum 10,04%; Silicon 31,35%; Oxygen 53,58%
13,96% BeO; 18,97% Al2O3; 67,07% SiO2
Density 2,76 average
Crystal system: hexagonal
Color: green, blue, yellow, colorless, pink and other
Crystal habit: prismatic, tabular crystals
Cleavage imperfect
Fracture conchoidal to irregular
Mohs scale 7,5-8
Luster vitreous to resinous
Streak white
Trasparent to translucent to opaque
Specific gravity 2,76
Optical properties uniaxial (-)
Pleochroism wheal to distinct
Rock type: igneous, metamorphic
Special characteristics:
None to weak fluorescence in Morganite, emerald
Fluorescence yellow, light blue, purple, pink or red
Common impurities: Fe, Mn, Mg, Ca, Cr, Na, Li, Cs, O, H, H2O, K, Rb
Tests:
Hardness of 7,5-8 Mohs
Insoluble in acids
Crystal form prismatic, tabular
Streak white
Varieties:
Aquamarine - shy blue to bluish green, mainly associated with granitic pegmatites
Bazzite - has some rare element scandium replacing some of the aluminium Be3(Al,Sc)2SiO6
Bixbite - a form of red beryl from Utah
Emerald - green variety of Beryl; contains chromium
Golden Beryl - golden yellow to orange yellow variety of Beryl
Goshenite - colorless or white variety of Beryl
Green Beryl - pale green variety of Beryl, distinguished from emerald which is a deeper green
Heliodor - greenish-yellow to yellow variety of Beryl, may also describe light green, orange and brown Beryl and can be interchangeable with Golden Beryl
Morganite - pink to light purple variety of Beryl
Pezzottaite - a newly identified raspberry red similar to Pezzottaite Beryl but contains lithium Cs(Be2Li)Al2(Si6O18)
Precious Beryl - transparent form of Beryl
Red Beryl - deep red form from Utah
Blue Beryl ( Maxixe ) - pleochoroic light sensitive variety containing 2,8% Cs2O and 1% Li2O; the color is caused by Co3
Alkali Beryl - variety of beryl with high in alkalis Li2O, Na2O, K2O, Rb2O, Cs2O
Aeroides - pale blue gem beryl
Amethiste basaltine of Egleston - violet beryl
Caesium beryl - cefers to caesium bearing beryl named vorobyevite and rosterite
Pachea - dark green chromium rich gem variety of beryl
Raspberyl - red beryl
Riesling beryl - leek green variety of beryl
Rosterite - alkali beryl
Common associations: Quartz, muscovite, albite, orthoclase, calcite, pyrite, spodumene, tourmaline, apatite
Distinguishing similar minerals:
Apatite - softer 5 Mohs
Quartz - softer 7 Mohs, different crystals strated horizontally where beryl striated vertically
Feldspars - softer 6 Mohs and good cleavage
Topaz - different crystal form
Tourmaline - different crystal form and heavily striated
Fluorescence
In long and short wave orange-yellow.
Other colors in short wave: bluish white, dark orange, dark yellow, bluish
Main common activator Cr 3+
Other activators: Fe 3+, Mn, V, VO
VO peak spectrum 433 nm
Mn tetrahedral 480 nm and octaedral 570 nm
Fe or V or Mn with peak at 720 - 745 nm
Cr or V has lines at 693 and 694 nm
Sources:
https://www.mindat.org/min-819.html
http://www.fluomin.org/uk/fiche.php?id=237&name=BERYL
https://www.minerals.net/mineral/beryl.aspx
http://webmineral.com/data/Beryl.shtml#.XdrmmugzZrQ
Other names: Emerald aquamarine red beryl smarald smaragn smaragnul smaraldul smaragd smaragdul beril berilul
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