List of Gemstones | Rare Minerals | Gem stones | Gems http://www.all-gemstones.com www.all-gemstones.com    Mon, 15 Mar 2010 12:06:08 +0000 http://wordpress.org/?v=2.8.6 en hourly 1 Star Sapphire http://www.all-gemstones.com/star-sapphire http://www.all-gemstones.com/star-sapphire#comments Mon, 15 Mar 2010 12:06:08 +0000 admin http://www.all-gemstones.com/?p=1340 Refractive Index : 1.770 – 1.762 (+0.009 – 0.005) Optical Characteristic : DR U-, AGG Specific Gravity : 4.00 (+0.10 – 0.05) Formula : AI2O3 Crystal System : Trigonal Variety/Species : Sapphire Species/Group : Corundum Birefringence : 0.008 to 0.010 Dispersion : 0.018 Hardness : 9 Toughness : Good to excellent Ultrasonic : Usually safe Steam : usually safe UV Long : Inert to strong UV Short : Inert to strong Pleochroism : 2 colors Strength : weak
Pleochroism Colors : weak to none Heat : stable Acids : No reaction Light : stable Polish Luster : vitreous to subadamantine Fracture : conchoidal Fracture Luster : Vitreous Clarity Type : ll Tones : N/A Saturations : N/A Cause of Color : Iron , chromium, and titanium Enhancements : Heating, diffusion, oil, dye Cleavage : None.Frequant parting. Color Range : Pink, purple, violet, green, blue, brownish yellow, grayish blue, reddish purple, bluish purple, bluish violet, violetish blue, greenish blue, green-blue, blue-green, bluish green, yellowish green, yellowish, pinkish, brownish, blackish, grayish Brown, black, gray, are considered black star sapphires. Transparency : Semitransparent to opaque Phenomena : Asterism, 6 ray star, 12 ray star Usually 6 ray.
Separations : Star Sapphire from-

Synthetic star sapphire : magnification, fluorescence (possibly)

Star spinel : RI, SG, optic character, magnification, spectrum

Star diopside : RI, SG, appearance Identifying Characteristics and information
Silk (fine needle-like rutile crystals), 3 sets of rutile neddles intersecting at 60 degree angles, fingerprint inclusions, hexagonal growth lines, and color zoning. Spectral Data
Lines at 4500, 4600, 4700. Trade Names and Misnomers
Star Sapphire
Star topaz (M) ]]> http://www.all-gemstones.com/star-sapphire/feed 0 Star spinel http://www.all-gemstones.com/star-spinel http://www.all-gemstones.com/star-spinel#comments Mon, 15 Mar 2010 12:03:20 +0000 admin http://www.all-gemstones.com/?p=1343 Refractive Index : 1.718 (+0.017 – 0.008) Optical Characteristic : SR Specific Gravity : 3.60 (+0.10 – 0.03) Formula : MgAI2O4 Crystal System : Cubic Variety/Species : spinel Species/Group : Spinel Group Birefringence : none Dispersion : 0.020 Hardness : 8 Toughness : good Ultrasonic : Usually safe Steam : usually safe UV Long : Inert to strong UV Short : Inert to weak Pleochroism : None Strength : N/A

Pleochroism Colors : None Heat : May change color Acids : No reaction Light : stable Polish Luster : vitreous to subadamantine Fracture : conchoidal Fracture Luster : Vitreous Clarity Type : N/A Tones : 2-8 Saturations : 1-5 Cause of Color : Blue – iron, cobalt(rare); Red/pink – chromium Enhancements : none Cleavage : None Color Range : Dark brownish red, purple, gray, black, reddish, purplish, grayish, blackish Transparency : Semitransparent to semitranslucent Phenomena : Aventurescence (rare), color change
Separations : Star spinel from-

Star Garnet : RI, spectrum, SG (possibly)

Star Ruby : optic character, magnification, pleochroism, optic character Identifying Characteristics and information
Tiny octahedral crystals arranged singly or in “fingerprint” patterns.

May have iron oxide staining. Spectral Data
Red: 5400. Blue: 4330, 4580, 4600, 4780, 5080, 5550, 5850, 6350, 6750, 6850. Trade Names and Misnomers
Star Spinel ]]> http://www.all-gemstones.com/star-spinel/feed 0 Tourmaline Group http://www.all-gemstones.com/tourmaline-group http://www.all-gemstones.com/tourmaline-group#comments Mon, 15 Mar 2010 12:01:26 +0000 admin http://www.all-gemstones.com/?p=1408 Refractive Index : 1.644 – 1.624 + 0.134 – 0.021 Optical Characteristic : DR U- Specific Gravity : 3.06 + 0.20 – 0.06 Formula : Na(Li,AI)3AI6(BO3)3Si6018(OH)4 Crystal System : Trigonal Variety/Species : All Species/Group : Tourmaline Group Birefringence : 0.018 to 0.040 Dispersion : 0.017 Hardness : 7 to 7.5 Toughness : Fair Ultrasonic : Risky Steam : Risky UV Long : Inert to weak UV Short : Inert to moderate Pleochroism : 2 colors Strength : Weak to strong

Pleochroism Colors : Press the Heat : May fracture or change color Acids : No reaction Light : Stable Polish Luster : Vitreous Fracture : Conchoidal Fracture Luster : Vitreous Clarity Type : I to III Tones : 2-8 Saturations : 1-5 Cause of Color : Varies:See variety Enhancements : Heating, Irradiation, acid treatment Cleavage : None Color Range : Almost any color is possible. Transparency : Transparent to Opaque Phenomena : Color change, (rare), aventurescence, Chatoyancy
Separations : Tourmaline Group from-

Topaz : birefringence, optic character, SG, cleavage, spectrum(possibly)

Andalusite : birefrigence, optic character, pleochrosim, SG

Peridot : RI, SG, birefringence, optic character, pleochrosim, spectrum

Iolite : RI, SG, optic character, pleochroism Identifying Characteristics and information

Thread-like liqiud and gas inclusions,gas filled fractures.
Birefringence is usually 0.018 – 0.020 but in dark stones it may be as high as 0.040. Spectral Data
Not diagnostic. Weak spectra usually observed Trade Names and Misnomers ]]> http://www.all-gemstones.com/tourmaline-group/feed 0 Sodalite http://www.all-gemstones.com/sodalite http://www.all-gemstones.com/sodalite#comments Fri, 05 Mar 2010 13:39:44 +0000 admin http://www.all-gemstones.com/?p=1307 Refractive Index : 1.483 (+0.004 – 0.004) Optical Characteristic : SR, AGG Specific Gravity : 2.25 (+0.15 – 0.10) Formula : Na8AI6Si6O24CI2 Crystal System : Cubic Variety/Species : sodalite Species/Group : Sodalite group Birefringence : none Dispersion : none Hardness : 5 to 6 Toughness : poor Ultrasonic : Never Steam : risky UV Long : Inert to weak UV Short : Inert Pleochroism : None Strength : N/A

Pleochroism Colors : None Heat : Fusible Acids : Avoid hydrofluoric acid Light : some may fade Polish Luster : vitreous to greasy Fracture : Uneven Fracture Luster : Vitreous to greasy Clarity Type : N/A Tones : N/A Saturations : N/A Cause of Color : Blue: color centers;pink: chlorine color centers Enhancements : none Cleavage : poor. Color Range : Dark, blue, violetish blue, violet, Sometimes, gray, greenish, yellowish white Often with white veins. Transparency : Semitransparent to opaque Phenomena : None
Separations : Sodalite from-
Lapis lazuli : RI, SG, magnification, fluorescence

Lazulite : RI, SG, pleochroism

Dumortierite quartz : RI, SG, magnification

Dyed Jasper : RI, SG, appearance Identifying Characteristics and information
White venis are common.

Rarely has pyrite inclusions.

Sodalite is usually more violet than lapis lazuli.

Orange phosphorescence. Spectral Data
not diagnostic. Trade Names and Misnomers
Canadian Lapis(M)
Ditroite
German Lapis (M)
Hackmanite (S)
Sodalite ]]> http://www.all-gemstones.com/sodalite/feed 0 Sphalerite http://www.all-gemstones.com/sphalerite http://www.all-gemstones.com/sphalerite#comments Thu, 28 Jan 2010 07:02:51 +0000 admin http://www.all-gemstones.com/?p=1313 Refractive Index : 2.50 – 2.369 Optical Characteristic : SR Specific Gravity : 4.05 (+0.05 – 0.15) Formula : ZnS + Fe Crystal System : Cubic Variety/Species : Sphalerite Species/Group : sphalerite Group Birefringence : none Dispersion : 0.156 Hardness : 3.5 to 4 Toughness : poor Ultrasonic : Never Steam : Never UV Long : Inert to strong UV Short : Inert to strong Pleochroism : None Strength : N/A

Pleochroism Colors : None Heat : sensitive Acids : Avoid hydrofluoric acid Light : stable Polish Luster : Adamantine Fracture : conchoidal, to uneven Fracture Luster : Adamantine to resinous Clarity Type : N/A Tones : N/A Saturations : N/A Cause of Color : yellow, orange, red, brown: iron Enhancements : none Cleavage : perfect dodecahedral. Color Range : Yellow, green, orange, brown, red, greenish brown, yellow-brown. Often has color zoning. Rarely, colorless. Transparency : Transparent to opaque Phenomena : Asterism, 6 ray star Asterism is extremely rare in spalerite.
Separations : Sphalerite from-
Spessarite : Spectrum, cleavage, dispersion, color(possibly)

Zircon : optic character, spectrum (possibly), magnification

Scheelite : SG, optic character, fluorescence, dispersion, cleavage

Andradite : magnification, spectrum, cleavage, dispersion (possibly)

Sphene : optic character, spectrum, SG, dispersion(possibly)

Curprite : SG, spectrum, color, dispersion, cleavage (possibly) Identifying Characteristics and information
RI increase with iron content.

Very strong dispersion.

Color zoning is common.

Rough often shows cleavage surfaces.

Generally inert, but may fluoresce moderate to strong orange-red (LW and SW).

Orange phosphorescence. Known as Blende in Europe. Spectral Data
Bands at 6510, 6900 (due to cadmium). Trade Names and Misnomers
Black Jack
Blende
Cleiophane(S)
False Galena
Marmatite(S)
Mock Lead Ore
Ruby Jack (M)
Schalenblende
Sphalerite
Wurtzite ]]> http://www.all-gemstones.com/sphalerite/feed 0 Spodumene http://www.all-gemstones.com/spodumene http://www.all-gemstones.com/spodumene#comments Thu, 28 Jan 2010 06:59:54 +0000 admin http://www.all-gemstones.com/?p=1321 Refractive Index : 1.676 – 1.662 (+0.005 – 0.005) Optical Characteristic : DR, B+ Specific Gravity : 3.18 (+0.03 – 0.03) Formula : LiAISi2O6 Crystal System : Monoclinic Variety/Species : spodumene Species/Group : Pyroxene group Birefringence : 0.014 Dispersion : 0.017 Hardness : 6.5 to 7 Toughness : poor Ultrasonic : Never Steam : Never UV Long : Inert UV Short : Inert Pleochroism : 2 colors Strength : moderate

Pleochroism Colors : Heat : sensitive Acids : Avoid hydrofluoric acid Light : stable Polish Luster : vitreous Fracture : Uneven to splintery Fracture Luster : Vitreous Clarity Type : l Tones : 2-4 Saturations : 1-4 Cause of Color : chromium Enhancements : lrradiation Cleavage : perfect 1 direction. Color Range : Pink, bluish purple, green, yellow, colorless, blue (very rare), pinkish, purplish, greenish, yellowish colored varieties light in tone. See also: Kunzite , Hiddenite, Triphane Transparency : Transparent Phenomena : chatoyancy, cat’s eye, Tenebrescence
Separations : Spodumene from-
Tourmaline : RI, birefringence, optic character, SG, fluorescence

Peridot : RI, SG, birefringence, Spectrum, cleavage

Beryl : RI, SG, optic character, cleavage

Komerupine : optic sign, SG, spectrum, fluorescence

Phenakite: optic character, SG, cleavage, fluorescence (possibly)

Euclase: birefringence, SG, cleavage, fluorescence, color (possibly) Identifying Characteristics and information
Liquid inclusions. Spectral Data
See varieties (Kunzite, Hiddenite, Triphane). Trade Names and Misnomers
Cat’s Eye Spodumene
Hiddenite (S)
Kunzite(S)
Pinite
Spodumene
Triphane (S) ]]> http://www.all-gemstones.com/spodumene/feed 0 Sphene http://www.all-gemstones.com/sphene http://www.all-gemstones.com/sphene#comments Wed, 20 Jan 2010 04:12:03 +0000 admin http://www.all-gemstones.com/?p=1315 Refractive Index : 2.034 – 1.900 (+0.020 – 0.020) Optical Characteristic : DR, B+ Specific Gravity : 3.52 (+0.02 – 0.02) Formula : CaTiSiO5 Crystal System : Monoclinic Variety/Species : All Species/Group : sphene Birefringence : 0.100 to 0.135 Dispersion : 0.051 Hardness : 5 to 5.5 Toughness : Fair to poor Ultrasonic : risky Steam : Never UV Long : Inert UV Short : Inert Pleochroism : 3 colors Strength : moderate to strong

Pleochroism Colors : Colorless/ green; colorless/ blue; pale yellow/ brownish yellow/ orange-brown. Heat : Avoid abrupt temperature change Acids : Attacked by acids and/or chemicals Light : stable Polish Luster : Adamantine Fracture : splintery to conchoidal Fracture Luster : Adamantine to resinous Clarity Type : N/A Tones : N/A Saturations : N/A Cause of Color : intense green: chromium: others: rare earth elements Enhancements : none Cleavage : distinct 1 direction. Color Range : Yellow, green, orange, brown, red, yellowish, greenish, orangy, brownish, reddish. Red is rare. Transparency : Transparent to translucent Phenomena : None
Separations : Sphene from-
Synthetic rutile : magnification, spectrum, SG, optic character

Zircon : optic character, spectrum, SG

Scheelite : SG, optic character, fluorescence, color (possibly)

Andradite : optic character, magnification, spectrum, cleavage

CZ/GGG/YAG : doubling, SG, magnification, spectrum Identifying Characteristics and information
Strong doubling, strong dispersion.
Twinning is common.
Avoid rough handling.
Also known as Titanite.
May show two directional cleavage with a 66.5 degree angle between them. Spectral Data
May have a doublet at 5800. Trade Names and Misnomers
Chrome Sphene(S)
Greenovite
Grothite
Keilhauite
Sphene
Titanite ]]> http://www.all-gemstones.com/sphene/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 Spurrite http://www.all-gemstones.com/spurrite http://www.all-gemstones.com/spurrite#comments Tue, 19 Jan 2010 05:49:20 +0000 admin http://www.all-gemstones.com/?p=1323 Refractive Index : 1.679 – 1.640 Optical Characteristic : DR, B- Specific Gravity : 3.00 Formula : Ca5(SiO4)2(CO3) Crystal System : Monoclinic Variety/Species : All Species/Group : spurrite Birefringence : 0.039 Dispersion : Hardness : 5 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 : vitreous Fracture : conchoidal Fracture Luster : Clarity Type : N/A Tones : N/A Saturations : N/A Cause of Color : Enhancements : none Cleavage : distinct 1 direction. Color Range : Gray, lavender gray, purple grayish, purplish Transparency : translucent to opaque Phenomena : None
Separations : Spurrite from- Identifying Characteristics and information
Rare. Spectral Data
not diagnostic Trade Names and Misnomers
Spurrite ]]> http://www.all-gemstones.com/spurrite/feed 0 Staurolite http://www.all-gemstones.com/staurolite http://www.all-gemstones.com/staurolite#comments Tue, 19 Jan 2010 05:47:43 +0000 admin http://www.all-gemstones.com/?p=1346 Refractive Index : 1.746 – 1.736 (+0.015 – 0.015) Optical Characteristic : DR, B+, AGG Specific Gravity : 3.71 (+0.08 -0.06) Formula : (Fe++,Mg)2AI9(Si,AI)4O20(O,OH)4 Crystal System : Monoclinic Variety/Species : All Species/Group : staurolite Birefringence : 0.009 to 0.015 Dispersion : 0.021 Hardness : 7 to 7.5 Toughness : fair Ultrasonic : risky Steam : risky UV Long : Inert UV Short : Inert Pleochroism : 3 colors Strength : moderate
Pleochroism Colors : Transparent brown stones: moderate, yellow to red, brownish yellow and colorless. Heat : stable Acids : slightiy attacked by acids Light : stable Polish Luster : vitreous to resinous Fracture : conchoidal, to uneven Fracture Luster : Dull to vitreous Clarity Type : N/A Tones : N/A Saturations : N/A Cause of Color : Iron and titanium Enhancements : Impregnation or wax/plastic coating Cleavage : distinct 1 direction. Color Range : Most often, brown, black. Rarely transparent brown. Transparency : Tranparent to opaque Phenomena : None
Separations : Staurolite from-
Chrysoberyl : RI, spectrum, birefringence (possibly)
Opaque staurolite twins have a very distinctive cross shaped appearance. Identifying Characteristics and information
Twin crystals occur at 90 or 60 degrees to one another.

Often left uncut in cross shapes.

Zincian staurolite is very rare but lighter in color and more attractive (when faceted) than staurolite.

Lusakite (also very rare) is cobaltian staurolite which is adeep blue.

It is strongly pleochroic. Spectral Data
Strong line near 4500. Weaker line near 5800. Rarely bands at 6100, 6320 and 5320. Trade Names and Misnomers
Cross Stones
Fairy Cross
Lusakite
Staurolite
Staurotide
Zincian Staurolite ]]> http://www.all-gemstones.com/staurolite/feed 0