List of Gemstones | Rare Minerals | Gem stones | Gems » Hexagonal http://www.all-gemstones.com www.all-gemstones.com    Thu, 06 May 2010 12:29:47 +0000 http://wordpress.org/?v=2.8.6 en hourly 1 Star Beryl http://www.all-gemstones.com/star-beryl http://www.all-gemstones.com/star-beryl#comments Thu, 06 May 2010 12:17:06 +0000 admin http://www.all-gemstones.com/?p=1326 Refractive Index : 1.583 – 1.577 (+0.017 – 0.017) Optical Characteristic : DR, U- Specific Gravity : 2.72 (+0.18 – 0.05) Formula : Be3Al2Si6O18 Crystal System : Hexagonal Variety/Species : Star Beryl Species/Group : Beryl Birefringence : 0.005 – 0.009 Dispersion : 0.014 Hardness : 7.5 to 8 Toughness : good Ultrasonic : risky Steam : risky UV Long : Inert UV Short : Inert Pleochroism : 2 colors Strength : weak
Pleochroism Colors : None Heat : Avoid heating Acids : Avoid hydrofluoric acid Light : some may fade Polish Luster : vitreous Fracture : conchoidal Fracture Luster : Vitreous to resinous Clarity Type : N/A Tones : N/A Saturations : N/A Cause of Color : Iron Enhancements : none Cleavage : Indistinct. Color Range : Yellowish brown, black, yellowish, brownish, blackish Transparency : Semitranslucent to opaque Phenomena : Asterism, 6 ray star
Separations : Star Beryl from- Identifying Characteristics and information
Six ray star but usually weak Spectral Data
Yellow green: band at 4375. weaker band at 4330. Trade Names and Misnomers
Star Beryl ]]> http://www.all-gemstones.com/star-beryl/feed 0 Sogdianite http://www.all-gemstones.com/sogdianite http://www.all-gemstones.com/sogdianite#comments Tue, 19 Jan 2010 05:51:19 +0000 admin http://www.all-gemstones.com/?p=1309 Refractive Index : 1608 – 1.606 Optical Characteristic : DR, U- Specific Gravity : 2.90 – 2.76 Formula : (K,Na)2Li,Fe,AI,Ti)2Zr2(Si2O5)6 Crystal System : Hexagonal Variety/Species : sogdianite Species/Group : Osumilite group Birefringence : 0.002 Dispersion : Hardness : 5 to 7 Toughness : poor Ultrasonic : Never Steam : Never UV Long : Inert to weak UV Short : Inert to weak Pleochroism : None Strength : N/A
Pleochroism Colors : None Heat : sensitive Acids : sensitive Light : stable Polish Luster : vitreous to waxy Fracture : conchoidal Fracture Luster : Clarity Type : N/A Tones : N/A Saturations : N/A Cause of Color : Enhancements : none Cleavage : perfect 1 direction. Color Range : violet, (bright) violetish Transparency : opaque Phenomena : None
Separations : Sogdianite from-
Sugilite : spectrum (possibly) Identifying Characteristics and information
Extremely rare.

Usually mixed with other minarals so RI and SG are variable.

May require chemical analysis to separate from sugilite. Spectral Data
Sharp lines at 4110, 4190 and 4370 (diagnostic). weak bands at 4880-4930 and 6300-6450. Trade Names and Misnomers
Sogdianite ]]> http://www.all-gemstones.com/sogdianite/feed 0 Taafeite http://www.all-gemstones.com/taafeite http://www.all-gemstones.com/taafeite#comments Tue, 12 Jan 2010 03:56:20 +0000 admin http://www.all-gemstones.com/?p=1374 Refractive Index : 1.723 – 1.719 (+0.002 – 0.002) Optical Characteristic : DR, U- Specific Gravity : 3.61 (+0.01 – 0.01) Formula : BeMg3AI8O16 + Fe, Mn, Zn, V, Cr. Crystal System : Hexagonal Variety/Species : All Species/Group : Taafeite Birefringence : 0.004 to 0.005 Dispersion : 0.019 Hardness : 8 to 8.5 Toughness : good Ultrasonic : risky Steam : risky UV Long : Inert to weak UV Short : Inert to weak Pleochroism : None Strength : N/A

Pleochroism Colors : None Heat : Avoid heating Acids : No reaction Light : stable Polish Luster : vitreous Fracture : conchoidal Fracture Luster : Vitreous Clarity Type : N/A Tones : N/A Saturations : N/A Cause of Color : pink and red – chromium Enhancements : none Cleavage : None Color Range : Pink, red, blue, violet, purple, brown, colorless, violetish blue, bluish violet, bluish purple, reddish purple Transparency : Transparent Phenomena : None
Separations : Taafeite from-
Spinel : optic character, birefringence Identifying Characteristics and information
No singular identifying characteristics.

Use the combination of properties.

May fluorescence weak green (LW and SW) Spectral Data
not diagnostic. Weak band at 4580. Trade Names and Misnomers
Magnesiotaafeite
Taafeite ]]> http://www.all-gemstones.com/taafeite/feed 0 Thaumasite http://www.all-gemstones.com/thaumasite http://www.all-gemstones.com/thaumasite#comments Sun, 10 Jan 2010 15:12:10 +0000 admin http://www.all-gemstones.com/?p=1388 Refractive Index : 1.507-1.464 Optical Characteristic : DR, U- Specific Gravity : 1.91 Formula : Ca38i(CO3)(804)(OH)6.12(H2O) Crystal System : Hexagonal Variety/Species : All Species/Group : Thaumasite Birefringence : .036 Dispersion : none Hardness : 3.5 Toughness : poor Ultrasonic : Never Steam : Never UV Long : Inert UV Short : Inert to moderate Pleochroism : None Strength : N/A

Pleochroism Colors : None Heat : sensitive Acids : sensitive Light : stable Polish Luster : vitreous to greasy Fracture : subconchoidal Fracture Luster : none Clarity Type : N/A Tones : N/A Saturations : N/A Cause of Color : None Enhancements : None Cleavage : Indidtinct Color Range : Colorless, white Transparency : Transparent to translucent Phenomena : Chatoyancy
Separations : Thaumasite from- Identifying Characteristics and information
Brittle. May cut catseye cabochons but the effect is fairly weak. Phosphorescene. Spectral Data
Not diagnostic Trade Names and Misnomers
Thaumasite ]]> http://www.all-gemstones.com/thaumasite/feed 0 Sugilite http://www.all-gemstones.com/sugilite http://www.all-gemstones.com/sugilite#comments Tue, 05 Jan 2010 04:03:33 +0000 admin http://www.all-gemstones.com/?p=1365 Refractive Index : 1.610 – 1.607 (+0.001 – 0.002) Optical Characteristic : DR U-, AGG Specific Gravity : 2.74 (+0.05) Formula : (K,Na)(Na,Fe+3)2(Li2,Fe+3)Si12O30 + Mn. Crystal System : Hexagonal Variety/Species : Sugilite Species/Group : Osumilite group Birefringence : None to 0.003 Dispersion : N/A Hardness : 5.5 to 6.5 Toughness : good Ultrasonic : risky Steam : risky UV Long : Inert UV Short : Inert Pleochroism : None Strength : N/A
Pleochroism Colors : None Heat : stable Acids : Avoid hydrofluoric acid Light : stable Polish Luster : waxy to vitreous Fracture : granular Fracture Luster : dull Clarity Type : N/A Tones : N/A Saturations : N/A Cause of Color : manganese, iron Enhancements : none Cleavage : None Color Range : Red-purple, reddish purple, purple, bluish purple, pink (rare), reddish Transparency : Semitransparent to opaque Phenomena : None
Separations : Sugilite from-
Charoite : RI, appearance, spectrum

Amethystine chalcedony : RI, SG, spectrum Identifying Characteristics and information
Purple color is intense.
May show RI of 1.54 due to quartz impurities. Spectral Data
Strong band at 4190, weak band at 4110 Broad, diffuse band centered at 5700. Lines at 4370, 4450 Trade Names and Misnomers
Royal Azel
Roysl Lavulite
Sugilite ]]> http://www.all-gemstones.com/sugilite/feed 0 Trapiche Emerald http://www.all-gemstones.com/trapiche-emerald http://www.all-gemstones.com/trapiche-emerald#comments Mon, 04 Jan 2010 10:49:19 +0000 admin http://www.all-gemstones.com/?p=1411 Refractive Index : 1.583-1.577 + 0.017 – 0.017 Optical Characteristic : DR, U- Specific Gravity : 2.72 + 0.18 – 0.05 Formula : Be3AI2Si6O18 Crystal System : Hexagonal Variety/Species : Trapiche emerald Species/Group : Beryl Birefringence : 0.005 to 0.009 Dispersion : 0.014 Hardness : 7.5 to 8 Toughness : Poor to good Ultrasonic : Never Steam : Never UV Long : Inert to strong UV Short : Inert to strong Pleochroism : 2 colors Strength : Moderate to strong

Pleochroism Colors : Moderate to strong : Green/blue green Heat : May fracture Acids : Avoid hydrofluoric acid Light : Stable Polish Luster : Vitreous Fracture : Conchoidal Fracture Luster : Vitreocs to resinous Clarity Type : III Tones : 3-8 Saturations : 2-5 Cause of Color : Usually chromium, sometimes vanadium, or both Enhancements : Oiling, opticon Cleavage : Indistinct Color Range : strongly, bluish green, green . Transparency : Transparent to translucent (highly included stones) Phenomena : None
Separations : Trapiche Emerald from-
Flux synthetic emerald (except Gilson Type III) : magnification, RI ,birefriegence, fluoresence, SG

Gilson Type III: Magnification, spectrum (possibly)

All triplets : Magnification, immersion, RI (possibly)

Hydrothermal synthetic emerald : Magnification, fluorescene

Hydrothermal overgrowth/sandwich : Magnification, fluorescene, immersion

Dioptase : RI, birefringence, SG, cleavage, magnification Identifying Characteristics and information
Colombian emeralds are characterized by 6 green to black spoke or arms .
Albite or carbonaceous inclusions cause the areas between the arms to appear black or grayish.
Pyrite, calcite and mica inclusions, 3-phase inclusions. Spectral Data
Lines at 6830 and 6805. Less distinct lines at 6620, 6460. Trade Names and Misnomers ]]> http://www.all-gemstones.com/trapiche-emerald/feed 0 Emerald http://www.all-gemstones.com/emerald http://www.all-gemstones.com/emerald#comments Tue, 08 Dec 2009 05:10:07 +0000 admin http://www.all-gemstones.com/?p=779
Refractive Index : 1.583 – 1.577 (+0.017 – 0.017)
Optical Characteristic : DR U-
Specific Gravity : 2.72 (+0.18 – 0.05)
Formula : Be3AI2Si6O18
Crystal System : Hexagonal
Variety/Species : Emerald
Species/Group : Beryl
Birefringence : 0.005 to .009
Dispersion : 0.014
Hardness : 7.5 to 8
Toughness : Poor to good
Ultrasonic : Never
Steam : Never
UV Long : Inert to strong
UV Short : Inert to strong
Pleochroism : 2 Colors
Strength : Moderate to strong
Pleochroism Colors : Moderate to strong blue-green/yellowish green or (rarely) blue/yellowish green.
Heat : May fracture
Acids : Avoid hydrofluoric acid
Light : Stable
Polish Luster : Vitreous
Fracture : Conchoidal
Fracture Luster : Vitreous to resinous
Clarity Type : III
Tones : 3-8
Saturations : 2-5
Cause of Color : Usually chromium,sometimes vanadium,or both
Enhancements : Oiling,Opticon
Cleavage : Indistinct.
Color Range : Strongly, bluish green, green
Transparency : Transparent to Translucent (highly included stones)
Phenomena : Chatoyancy, Asterism. Asterism is rare.
Separations : Natural Emerald from-
Flux syn.emerald (except Gllson type III) : Magnification, RI, birefringence, fluorescence, SG

Gilson Type III : Magnification, spectrum (possibly)

All triplets : Magnificaation, immersion, RI(poosibly)

Hydrothermal synthetic emerald : Magnification, fluorescence

Hydrothermal overgrowth/sandwich : Magnification, fluorescence,immersion

Dioptase : RI, birefringence, SG, cleavage, magnification
Identifying Characteristics and information
Pyrite, calcite and mica inclusions, tremolite needles, 9-phase inclusions.
Spectral Data
Distinct lines at 6830 and 6805. Less distinct at 6620,6460. Partial absorption between 6300 and 5800
Trade Names and Misnomers
Brazilian Emerald
Colombian Emerald
Emerald
Russian Emerald
Sandawana Emerald
Siberian Emerald
Zambian Emerald
]]> http://www.all-gemstones.com/emerald/feed 0 Algodonite http://www.all-gemstones.com/algodonite http://www.all-gemstones.com/algodonite#comments Tue, 18 Aug 2009 04:42:57 +0000 admin http://www.all-gemstones.com/?p=378   Refractive Index : 0.00 Optical Characteristic : DR, Uniaxial, Agg Specific Gravity : 8.38 – 7.92 Formula : Cu6As Crystal System : Hexagonal Variety/Species : All Species/Group : Algodonite Birefringence : Dispersion : Hardness : 3 to 4 Toughness : Poor Ultrasonic : Never Steam : Never UV Long : Inert UV Short : Inert Pleochroism : None Strength : N/A

Pleochroism Colors : None Heat : Sensitive Acids : Sensitive Light : Stable Polish Luster : Metallic Fracture : Uneven to subconchoidal Fracture Luster : Clarity Type : N/A Tones : N/A Saturations : N/A Cause of Color : Enhancements : None Cleavage : None. Color Range : Silver white, white, steel gray, gray, brown, dull brown.  Transparency : Opaque Phenomena : None
Separations : Algodonite from- Identifying Characteristics and information
Tarnishes so quickly (to a dull brown) that they must be lacquered immediately after cutting.Cut for collectors only. Spectral Data
Not Diagnostic. Trade Names and Misnomers
Algodonite
Domeykite
Mohawkite
Whitneyite   ]]> http://www.all-gemstones.com/algodonite/feed 0 Vanadinite http://www.all-gemstones.com/vanadinite http://www.all-gemstones.com/vanadinite#comments Sat, 15 Aug 2009 04:47:53 +0000 admin http://www.all-gemstones.com/?p=1453   Refractive Index : 2.416 – 2.350 Optical Characteristic : DR, Uniaxial negative Specific Gravity : 7.10 – 6.80 Formula : Pb5(VO4)3CI Crystal System : Hexagonal Variety/Species : Vanadinite Species/Group : Apatite Group Birefringence : 0.066 Dispersion : 0.202 Hardness : 3.5 to 4 Toughness : Poor Ultrasonic : Never Steam : Never UV Long : Inert UV Short : Inert Pleochroism : 2 colors Strength : weak
Pleochroism Colors : Very weak shades of orange and yellow Heat : Sensitive Acids : Sensitive Light : Stable Polish Luster : Resinous to adamanitine Fracture : Conchoidal Fracture Luster : Clarity Type : N/A Tones : N/A Saturations : N/A Cause of Color : Enhancements : None Cleavage : None Color Range : Red, orange, orange-red, brownish red, brownish yellow, yellow, pale yellow, brown (rarely), colourless Transparency : Transparent to opaque Phenomena : None
Separations : Vanadinite from- Identifying Characteristics and information
Brittle, Often color zoned. Extremely rare but with a rich and beautiful color. Faceted gems almost always less than 1 carat Spectral Data
Not diagnostic Trade Names and Misnomers
Endlichite
Vanadinite   ]]> http://www.all-gemstones.com/vanadinite/feed 0