List of Gemstones | Rare Minerals | Gem stones | Gems » Natural Gemstones 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 Smoky Quartz http://www.all-gemstones.com/smoky-quartz http://www.all-gemstones.com/smoky-quartz#comments Thu, 06 May 2010 12:27:36 +0000 admin http://www.all-gemstones.com/?p=1303 Refractive Index : 1.553 – 1.544 Optical Characteristic : DR, U+, AGG Specific Gravity : 2.651 (+0.04 – 0.01) Formula : SiO2 Crystal System : Trigonal Variety/Species : smoky Species/Group : Quartz Birefringence : 0.009 Dispersion : 0.013 Hardness : 7 Toughness : good Ultrasonic : Usually safe Steam : risky UV Long : Inert UV Short : Inert Pleochroism : 2 colors Strength : weak
Pleochroism Colors : Dark stones, weak: Brown/reddish brown. Light stones, weak: light and darker yellowish brown. Heat : Avoid heating Acids : Avoid hydrofluoric acid Light : stable Polish Luster : vitreous Fracture : conchoidal Fracture Luster : Vitreous Clarity Type : l Tones : N/A Saturations : N/A Cause of Color : Aluminum impurities Enhancements : lrradiation, heating Cleavage : None Color Range : Light to dark, brown, gray, black Brownish, grayish, blackish Black variety is also called morion. Transparency : Transparent Phenomena : None
Separations : Smoky Quartz from-
Beryl: RI, optic character, optic figure (possibly), SG (possibly)

Topaz: RI, SG, optic character, cleavage

Synthetic Quartz: magnification, twinning pattern (as visible under polarized light) Identifying Characteristics and information
Color zoning, 2 and 3 phase liquid inclusions negative crystals, sometimes bull’s eye or Airy’s spiral optic figure.

Also known as Cairngorm.

Incorrectly called smoky topaz. Spectral Data
not diagnostic. Trade Names and Misnomers
Brown Quartz
Cairngorm(2)
Colorado Diamond(M)
Radium Diamond(M)
Smoky citrine(M)
Smoky Quartz
Smoky Topaz(M) ]]> http://www.all-gemstones.com/smoky-quartz/feed 0 Spinel – Synthetic http://www.all-gemstones.com/spinel-synthetic http://www.all-gemstones.com/spinel-synthetic#comments Thu, 06 May 2010 12:21:07 +0000 admin http://www.all-gemstones.com/?p=1319 Refractive Index : 1.728 (+0.012 – 0.008) Optical Characteristic : SR, ADR Specific Gravity : 3.64 (+0.02 – 0.12) Formula : MgAI2O4 Crystal System : Cubic Variety/Species : All Species/Group : Synthetic spinel Birefringence : none Dispersion : .020 Hardness : 8 Toughness : good Ultrasonic : Usually safe Steam : usually safe UV Long : Inert to strong UV Short : Inert to strong 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 : N/A Saturations : N/A Cause of Color : Blue – iron, cobalt; Red/pink – chromium Enhancements : none Cleavage : None Color Range : Colorless, blue, yellow, green, Violet, orange, (rare), pink, red, (rare) opaque dark blue (lapis lazuli imitation) Violetish, bluish, greenish, yellowish, orangy, pinkish, reddish Transparency : Transparent to opaque Usually transparent. Phenomena : Color change
Separations : Spinel – Synthetic from-
Natural spinel: RI (except red and blue), magnification, polariscope reaction,
fluorescence (except red and pink)

Natural Red Spinel: magnification

Natural blue Spinel: magnification, spectrum, polariscope reaction, fluoriscence,
color filter reaction (possibly)

All corundum: RI, SG, birefringence, optic character, magnification, fluorescence, spectrum Identifying Characteristics and information
Cross hatch effect in polariscope, gas bubbles, curved striae in red variety. Spectral Data
Typical of dopant used. Natural blue spinel has 4600 band due to iron(not currently seen in syn. spinel). Trade Names and Misnomers
Alumag
Aqua Gem (M)
Aquagem
Berylite
Brazilian emerald (M)(2)
Corundolite
Dirigem
Emerada
Hope sapphire (M) ]]> http://www.all-gemstones.com/spinel-synthetic/feed 0 Star Diopside http://www.all-gemstones.com/star-diopside http://www.all-gemstones.com/star-diopside#comments Thu, 06 May 2010 12:18:29 +0000 admin http://www.all-gemstones.com/?p=1329 Refractive Index : 1.701 – 1.675 (+0.029 – 0.010) Optical Characteristic : DR, B+,  AGG Specific Gravity : 3.29 (+0.11 – 0.07) Formula : CaMgSi2O6 Crystal System : Monoclinic Variety/Species : Diopside Species/Group : Pyroxene group Birefringence : 0.024 to 0.030 Dispersion : N/A Hardness : 5.5 to 6 Toughness : poor Ultrasonic : risky Steam : Never UV Long : weak UV Short : Inert Pleochroism : 2 or 3 colors Strength : weak to strong

Pleochroism Colors : None Heat : fusible Acids : Avoid hydrofluoric acid Light : stable Polish Luster : vitreous to resinous Fracture : conchoidal, to uneven Fracture Luster : Vitreous to resinous Clarity Type : N/A Tones : N/A Saturations : N/A Cause of Color : Green – chromuum; green/brown- iron Enhancements : none Cleavage : perfect 1 direction. Color Range : Dark: Green, black Greenish, Blackish Transparency : Semitransparent to opaque Phenomena : Adularescence, 4 ray star, 6 ray star most often 4 ray
Separations : Star Diopside from-
Black star sapphire: 4 rays (possibly), RI, SG Identifying Characteristics and information
Star usually has 4 rays instead of 6.

May show only 2 colors of pleochoroism. Spectral Data
5050 line is common. Trade Names and Misnomers
Indian Star Sapphire(M)
Star Diopside
Star of India(M) ]]> http://www.all-gemstones.com/star-diopside/feed 0 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 Star Enstatite http://www.all-gemstones.com/star-enstatite http://www.all-gemstones.com/star-enstatite#comments Thu, 06 May 2010 12:15:15 +0000 admin http://www.all-gemstones.com/?p=1332 Refractive Index : 1.673 – 1.663 (+0.010 – 0.010) Optical Characteristic : DR, B+ Specific Gravity : 3.25 (+0.15 – 0.02) Formula : MgSiO3 Crystal System : Orthorhombic Variety/Species : Enstatite Species/Group : Pyroxene group Birefringence : 0.008 to 0.011 Dispersion : none Hardness : 5 to 6 Toughness : poor Ultrasonic : risky Steam : Never UV Long : Inert UV Short : Inert Pleochroism : 2 or 3 colors Strength : weak to strong
Pleochroism Colors : Press the Heat : sensitive Acids : Avoid hydrofluoric acid Light : stable Polish Luster : vitreous Fracture : Uneven Fracture Luster : Vitreous to pearly Clarity Type : N/A Tones : N/A Saturations : N/A Cause of Color : Iron Enhancements : none Cleavage : good in 1 directipn. Color Range : Dark, reddish brown, brownish green, yellowish green Colorless, (rarely). Brownish, greenish Transparency : Semitransparent to opaque Phenomena : Adularescence, 4 ray or 6 ray
Separations : Star Enstatite from-
Star Diopside : birefringence, spectrum, color (possibly) Identifying Characteristics and information
No identifying characteristics.
Use a combination of properties.
Enstatite is part of a mineral series with hypersthene (which has higher properties).
May show pnly 2 colors of plechroism. Spectral Data
Strong line at 5060. Often lines at 5475 and 4880. May have lines at 5090, 5025, 4830, 4590, 4490. Trade Names and Misnomers
Star Enstatite ]]> http://www.all-gemstones.com/star-enstatite/feed 0 Star Ruby http://www.all-gemstones.com/star-ruby http://www.all-gemstones.com/star-ruby#comments Thu, 06 May 2010 12:12:51 +0000 admin http://www.all-gemstones.com/?p=1337 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 : Ruby 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 : may alter color or star Acids : slightiy attacked by acids Light : stable Polish Luster : vitreous to subadamantine Fracture : conchoidal Fracture Luster : Vitreous Clarity Type : ll Tones : N/A Saturations : N/A Cause of Color : chromium; possibly modified by iron and titanium Enhancements : Heating, diffusion, oil, dye Cleavage : None. Frequant parting. Color Range : Red, purplish red, purple-red, red-purple Reddish, purplish Transparency : Semitransparent to opaque Phenomena : Asterism, 6 ray star, 12 ray star Usually 6 ray.
Separations : Star Ruby from-
Synthetic star ruby : magnification, fluorescence (possibly)

Star Almandite : optic character, magnification, plechroism, spectrum,
fluorescence (possibly), RI (possibly)

Star Spinel : optic character, magnification, pleochroism. Identifying Characteristics and information
Silk (fine needle-like rutile crystals), 3 sets of rutile needles intersecting at 60 degree angles hexagonal growth lines, and color zoning. Spectral Data
Strong doublet @ 6942/6928. Weaker lines @ 6680 and 6592. Also lines @ 4765, 4750 and 4685. Trade Names and Misnomers
Star Ruby ]]> http://www.all-gemstones.com/star-ruby/feed 0 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 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