List of Gemstones | Rare Minerals | Gem stones | Gems » Species

Smoky Quartz

admin — Thu, 06 May 2010 12:27:36 +0000

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)

Star Sapphire

admin — Mon, 15 Mar 2010 12:06:08 +0000

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)

Tiger’s Eye

admin — Wed, 06 Jan 2010 05:33:09 +0000

Refractive Index : 1.553-1.554

Optical Characteristic : DR, AGG

Specific Gravity : 2.651 +.06 -.01

Formula : SiO2

Crystal System : Trigonal

Variety/Species : Tiger’s Eye

Species/Group : Quartz

Birefringence : 0.009

Dispersion : N/A

Hardness : 7

Toughness : Good

Ultrasonic : Uaually safe

Steam : Risky

UV Long : Inert

UV Short : Inert

Pleochroism : None

Strength : N/A

Pleochroism Colors : None

Heat : Avoid aburt temperature change

Acids : avoid hydrofluoric acid

Light : Stable

Polish Luster : Vitreous

Fracture : Splintery to conchoidal

Fracture Luster : Vitreous to silky

Clarity Type : N/A

Tones : N/A

Saturations : N/A

Cause of Color : Iron oxide

Enhancements : Heating, dyeing, bleaching

Cleavage : None

Color Range : Brownish yellow, brownish red, yellowish brown, yellowish, brownish, reddish.

Transparency : Semitranslucent to Opaque

Phenomena : chatoyancy, cat’s eye

Separations : Tiger’s Eye from-
Chalcedony : Appearance, fracture, RI(possibly)

Labradorite : RI, SG, optic character, clevage, labradirescence, twinning.

Chrysoberyl : RI, SG, appearance(possibly)

Tourmaline : RI, SG, spectrum

Actinolite:RI,SG(possibly)

Identifying Characteristics and information
Wavy, fibrous composition .

Spectral Data
Not diagnostic

Trade Names and Misnomers
Crocidolite(M)
Tiger Iron
Tiger`s Eye

Trapiche Emerald

admin — Mon, 04 Jan 2010 10:49:19 +0000

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

Triphane

admin — Sat, 26 Dec 2009 04:59:59 +0000

Refractive Index : 1.676 – 1.660 + 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 to0.016

Dispersion : 0.017

Hardness : 6.5 to 7

Toughness : Poor

Ultrasonic : Never

Steam : Never

UV Long : Inert to moderate

UV Short : Inert to moderate

Pleochroism : 2 or 3 colors

Strength : weak to moderate

Pleochroism Colors : Weak to moderate: Light yellow/ very light yellow.

Heat : Sensitive

Acids : Avoid hydrofluoric acid

Light : some may fade

Polish Luster : vitreous

Fracture : Uneven to splintery

Fracture Luster : Vitreous

Clarity Type : I

Tones : N/A

Saturations : N/A

Cause of Color : Iron

Enhancements : Irradiation

Cleavage : perfect in 1 direction.

Color Range : Yellow Yellowish

Transparency : Transparent

Phenomena : None

Separations : Triphane from-
Phenakite : Optic character, SG, Cleavage, fluorescene(possibly)

Euclase : Birefringence, SG, cleavage, fluorescence, color(possibly)

Beryl : RI, SG, optic character, cleavage

Identifying Characteristics and information
May have loquid inclusions.

May show only 2 colors of pleochrosim.

Spectral Data
Lines at 4330 and 4380.

Trade Names and Misnomers
Triphane

Turritella Agate

admin — Fri, 25 Dec 2009 05:04:28 +0000

Refractive Index : 1.54 – 1.53

Optical Characteristic : AGG

Specific Gravity : 2.60 + 0.30 – 0.05

Formula : SiO2

Crystal System : Trigonal

Variety/Species : Chalcedony

Species/Group : Cryptocrystaline Quartz

Birefringence : 0.004

Dispersion : None

Hardness : 6.5 to 7

Toughness : Good

Ultrasonic : Uaually safe

Steam : Usually safe

UV Long : Inert to moderate

UV Short : Inert to moderate

Pleochroism : None

Strength : N/A

Pleochroism Colors : None

Heat : May change color

Acids : Acids may attack dyes

Light : Stable

Polish Luster : Greasy to vitreous

Fracture : Conchoidal, may be granular

Fracture Luster : Dull to vitreous

Clarity Type : N/A

Tones : N/A

Saturations : N/A

Cause of Color : Iron

Enhancements : None

Cleavage : None or indistinct

Color Range : Brown, gray, black, with small spiral shells, brownish, grayish, blackish

Transparency : opaque

Phenomena : None

Separations : Turritella Agate from-
Glass : magnification, fracture luster, RI, SG, fracture, (all possibly)

Identifying Characteristics and information
Dark brown body color with small spiral shells.

The fossil shells aren’t actually in the Turritella family.

They are Oxyterma genera fossils

Spectral Data
Not diagnostic

Trade Names and Misnomers
Shell Agate
Turrite Agate

Emerald

admin — Tue, 08 Dec 2009 05:10:07 +0000

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

Vanadiumdravite

admin — Sat, 15 Aug 2009 04:51:59 +0000

Refractive Index : 1.786 – 1.729

Optical Characteristic : DR, uniaxial negative

Specific Gravity : 3.32

Formula : NaMg3V6(Si6O18)(BO3)3(OH)4

Crystal System : Trigonal

Variety/Species : Tourmaline

Species/Group : Tourmaline Group

Birefringence : 0.057

Dispersion : 0.017

Hardness : 7.5

Toughness : Fair

Ultrasonic : Risky

Steam : Risky

UV Long : Inert

UV Short : Inert

Pleochroism : 2 colors

Strength : Moderate to strong

Pleochroism Colors : No data

Heat : May fracture or change color

Acids : No reaction

Light : Stable

Polish Luster : Resinuous

Fracture :

Fracture Luster :

Clarity Type : N/A

Tones : N/A

Saturations : N/A

Cause of Color : N/A

Enhancements : None

Cleavage : None

Color Range : Dark green, green, black greenish, blackish

Transparency : Translucent to opaque

Phenomena : None

Separations : Vanadiumdravite from-

Identifying Characteristics and information
Thread-like liquid and gas inclusions, gas filled fractures.Vanadiumdravite is a very rare stone and not often seen as a gem.

Spectral Data
Not diagnostic

Trade Names and Misnomers
Vanadiumdravite

Variscite

admin — Thu, 13 Aug 2009 07:43:34 +0000

Refractive Index : 1.590 – 1.560 (+ 0.003 – 0.006)

Optical Characteristic : DR, AGG

Specific Gravity : 2.50 (- 0.10 + 0.10)

Formula : AIPO4.2(H2O)

Crystal System : Orthorhombic

Variety/Species : All

Species/Group : Variscite

Birefringence : Not detectable

Dispersion : N/A

Hardness : 3.5 to 5

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 : Attacked by acids and/or chemicals

Light : Stable

Polish Luster : Waxy to vitreous

Fracture : Granular to uneven

Fracture Luster : Dull

Clarity Type : N/A

Tones : N/A

Saturations : N/A

Cause of Color : Chromium and iron

Enhancements : None

Cleavage : Good in 1 direction

Color Range : Light to medium, yellowish green, bluish green. Often mottled or veined with yellow to brown matrix.

Transparency : Translucent to opaque

Phenomena : None

Separations : Variscite from-
Natural Turquoise Gemstone : color filiter, RI, appearance, spectrum, SG(possibly)Jadeite : RI, SG, spectrum, appearanceGlass : fracture luster, magnification, RI(possibly), spectrum(poss)Plastic : SG, magnification, RI(possibly), spectrum(possibly)Serpentine : RI(possibly), spectrum, color filter, appearance

Malachite : appearance, RI, SG

Identifying Characteristics and information
Yellow to brown matrix, stone appears pinkish through the color filter

Spectral Data
Strong line at 6880. Weaker line at 6500

Trade Names and Misnomers
Amatrix
Australian Jade (M)
Australian Turquoise (M)
Barrandite
Bolivarite
California Turquoise (M)
Lucinite
Nevada Turquoise (M)
Sabalite
Strengite

Amatrice

Utahlite

Trainite

Viridine

admin — Wed, 12 Aug 2009 12:52:01 +0000

Refractive Index : 1.643 – 1.634 (+ 0.005 – 0.005)

Optical Characteristic : DR, Biaxial negative, AGG

Specific Gravity : 3.17 + 0.04 – 0.04

Formula : AI2SiO5=AI[6]A[5]OSiO4

Crystal System : Orthorhombic

Variety/Species : Andalusite

Species/Group : Andalusite

Birefringence : 0.007 – 0.003

Dispersion : 0.016

Hardness : 7 to 7.5

Toughness : Fair to good

Ultrasonic : Uaually safe

Steam : Risky

UV Long : Inert

UV Short : Inert to moderate

Pleochroism : 2 or 3 colors

Strength : Strong

Pleochroism Colors : Strong(usually):Yellow/green/red

Heat : Stable unless has liquid inclusions

Acids : No reaction

Light : Stable

Polish Luster : Vitreous

Fracture : Uneven to conchoidal

Fracture Luster : Vitreous

Clarity Type : II

Tones : 3-6

Saturations : 2-4

Cause of Color : Green-maganese

Enhancements : Heating, dyeing

Cleavage : Distinct in 1 direction

Color Range : Green, greenish

Transparency : Transparent to opaque

Phenomena : None

Separations : Viridine from-Tourmaline : Birefringence, optic character, pleochroism, SG, spectrum(possibly)

Chrysoberyl : RI, SG, pleochroism, spectrum

Apatite : optic character, pleochroism, birefringence, color, spectrum

Identifying Characteristics and information
Strong pleochroism, usually yellow/green/red, needle-like inclusions(rutile crystals). May fluoresce green to yellowish green(SW). Andalusite is trimorphous with kyanite and sillimanite. May show only 2 colors of pleochroism

Spectral Data
Shadow at 5535, lines at 5505,5475; faint at 5180,4950,4550

Trade Names and Misnomers
Viridine