(Characteristic and properties of important gemstones)

1
????? 4 ?????????????????????????????
(Characteristic and properties of important
gemstones)
4.1 ???? (Diamond)
?????????????????????? (industrial diamond)
???????? 2 variety ????? ???
??????? 4 ????
???????????????????? N ??? B ???????
??????????????????? N
Type II b
Type I b
Type II a
Type I a
2
Type I a
? ???????? 98
? ?? N ??? ???????????????????(aggregate)
?????????? C
????????????????
? ??????? ?????????????? ????????????
????????
Type I b
? ?????????? 1 ????????????????????
? ?? N ???????? type I a
?????????????????????
? ?????????????????? type I a
3
Type II a
? ?????????
? ?? N ??????????????????
? ???????????????
Type II b
? ?????????? type I b ??? II a
? ?? B ??????? N
? ??????????? ??????? ???????????????
? ???????????????????????
????????????????????? Infrared spectroscopy
4
Crystallography
? ???? isometric
? ??????? octahedron ????? cube
dodecahedron ??? tetrahexahedron
??????? ????? ??????? (macle)
5
Physical properties
Cleavage ? perfect octahedron
S.G. ? 3.52
Thermal conductivity ? ?????????????????????

?????????????? ???????? Diamond tester
?????????????????????(moissanite) ??????????
Optical properties
Luster ? adamantine
Transparency ? ???????
Optic character ? isotropic
R. I. ? 2.417
Dispersion ? 0.044
6
Fluorescence ? ????????????????????? ??????
LWUV ??? SWUV
Absorption spectrum ? cape series
?????????? 415.5 nm.
7
Colour
????????????? ??????????????????? ???????????
??????? ?????????? ??? ??? ??? ????? ??? ???
???????????????? ?????????? ??????????
8
Chemical properties
Group ? Native element
Formula ? C
???????????????????????? C ????????????????????
??????????? covalent ??? C ??? 4 ?????
Diagnostic features
? ??????????????
? ????? R.I. ?????????????
? ??? ?.?. 3.52
? H 10
9
???????????? (diamond simulants)
1. Strontium titanate (SrTiO3)
H 5 1/2
?.?. 5.13
R.I. 2.41 ???????????????? Dispersion
0.19
2. YAG (Y3Al2(AlO4)3
???? yttrium aluminum garnet
R.I. 1.833 Dispersion 0.028 H
8
3. ???? GGG ( Gd3Ga2(GaO4)3
???? gadolinium gallium garnet
?.?. 7.05 -----gt ?????? R.I. 1.970
???????????
Dispersion 0.045 H 6 1/2
4. Cubic zirconia (ZrO2) ???? CZ ????
???????????
??????????????????????????????????????????
?.?. 5.80 R.I. 2.150
Dispersion 0.060 H 8 1/2
10
5. ?????????(moissanite) ????????????? (Mois)
----gt ???? SiC
?.?. 3.32 R.I. 2.648
-2.691
Dispersion 0.104 ?????????????? H 9
1/2
????????????????????????????????????
1. ??????????? (Read Through Test)
???????????????????????? ??????????????????
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????????????????????????????????
2. ??????????????????????????

• ?????????????????????? ?????????????????????

???? 3.52 ????? 4.60 -
4.70 ????????? 3.22 ??????????? 5.56
- 6.00

• ???????????????????????????? (Presidium)

???????????????????? ?????????????????????????????
???????? ????????????????????????
??????????????????????????????
12
???????????????????????
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Koh - i Noor (108.93 ct.)
The Worlds Great Diamond
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????????????????????????? round brilliant
table
crown
girdle
pavilion
culet
15
??????????? ?????????????????? ??????????????
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4.2 ???????? (Corundum)
??????????? 2 variety ???
1. ?????? (ruby)
?????????????
2. ??????? (sapphire)
??????????????? ???????????

• ??????? (sapphires) ???????? ????

????????? ???????? ????? ???? blue
sapphire
???????? ???????? ???????? ???? yellow
sapphire
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??????? ???????? ????????? ????
???????????? ???? green sapphire
?????? ???????? pink sapphire
????? ???????? orange sapphire
?????? ???????? purple sapphire
??????????? ???????? ??????????
???? ??????????? (padparadcha)
???????????????? ???? ???????????? ???? star
ruby / star sapphire
????????????????? ???? colour changed corundum
18
???????????????
1. ????????????? (Crystallography)
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????????????????????
Hardness 9 S.G. 4.00
???????? Al2O3
Cr 3 (Cr2O3 0.1 )
??????? ???????
Fe 3 ,V 3
????????
Cr 3 (Cr2O3 0.03 - 0.04 )
??????
Fe 3 - O - Ti 4
?????????
Fe 2 - O - Fe3
??????????????
colour center Fe 2 / Fe3
????????
Cr 3 ???/ ???? V 3 Fe 3 - O - Ti 4
????????????? (colour change)
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Optical properties
Luster subadamantine - vitreous
Transparency transparent to translucent
Optic character Uni -
Birefringence 0.008 - 0.010
Dispersion 0.018
Pleochroism ??????????????????????? ??????
yellow sapphire
Fluorescence ruby LWUV --gt
??????????-???????
SWUV ---gt ???-???????????? Inert
pink sapphire LWUV --gt ????? - ????????
blue sapphire ??????????????
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Absorption spectrum
ruby ( Cr)
blue sapphire (Fe)
yellow sapphire (Fe)
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Chemical properties
Chemical formula Al2O3
Group oxide (????? haematite)
?????????????????????????????????????????
(hexagonal closed packing)
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Occurrence
???? ???????? ---gt syenite nepheline
syenite basalt ??? pegmatite
?????? ---gt schist

• ??????????? ??????????????? alluvial

?????????? ??? Southeast Asia Myanmar
Thailand Laos Cambodia Vietnam
?????????? ?????? Sri Lanka Australia
Afghanistan Pakistan China India
Madagascar Kenya Tanzania Canada ???
Montana ?? USA. Columbia ??? Brazil
Name
Corundum ???????????????? Kauruntaka
?????? ??? Sapphire ????????????? ??????
????????? Ruby ?????????????? Ruber
?????? ?????
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????? ruby ??? sapphire ?? Southeast Asia
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Species Corundum
orange sapphire
yellow sapphire
blue sapphire
ruby
colourless sapphire
pink sapphire
green sapphire
purple sapphire
colour-change sapphire
padparadscha
yellow-green sapphire
black star sapphire
star ruby
star sapphire
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4.3 ????? (Beryl)
??????????? variety ??????
Emerald (Cr)
Green beryl (V)
Aquamarine (Fe)
Golden beryl (Fe)
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Goshenite
Maxixe
Morganite (Mn2)
Red beryl (Mn3)
Trapiche
Star emerald
Cats eye beryl
???????? emerald ??? aquamarine
???? emerald ??? Columbia
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Crystallography
Hexagonal --gt 1st order prism ??? basal
pinacoid
Physical properties
Cleavage ??????????
Fracture ?????????
Hardness 7 1/2 - 8
S.G. 2.72 (0.18 ??? -0.05)
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Optical properties
Luster vitreous
Transparency transparent to translucent
Optic character Uni -
Birefringence 0.005 - 0.009
Dispersion 0.014
Pleochroism emerald ---gt ??????????
????? ???? ??????????????
aquamarine ---gt ?????????? ??????? ????
??????????????
morganite ---gt ?????????? ??? ???? ?????????
golden beryl ---gt ?????????? ?????????????
??????????????????
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Fluorescence emerald ---gt
??????????? ??????????????????
aquamarine ---gt ???????????
morganite ---gt ??????????? ??????????????
?????????????
goshenite ---gt ???????????
??????????????????? - ?????????
Absorption spectrum emerald ---gt ???? Cr
??? 683 ??? 680.5 nm.
aquamarine ---gt ???????? ??? 537 ??? 456
nm.
?????????????? ??? 427 nm.
Chemical properties
Chemical formula Be3Al2Si6O18
Group Sorosilicate
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Occurrence

• Beryl ??????? pegmatite ?????? granite

• Beryl ???????? ????????????????????? cavity
  ?????? pegmatite

• ????????????? beryl ????????????????????? ???
  Columbia ?????????? ???????????????????????????
  ?(hydrothermal)

Name
beryl ??????????????????
beryllos ???????????????????????
emerald ????????????? smaragdos
?????? ?????
aquamarine ?????????????? ?????? ???????
morganite ????????? J.P. Morgan
heliodor ????????????? helios
?????? ??????????
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Diagnostic features
???????????????????? emerald ??????
jade
green zircon
peridot
green tourmaline
green garnet
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Species Beryl
Aquamarine
Emerald
Green beryl
Red beryl
Golden beryl
Morganite
Goshenite
Maxixe
Cats eye beryl
Trapiche
Star emerald
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4.4 ?????????? (Chrysoberyl)
??????? 3 variety ???
1. Chrysoberyl ?????????? ?????????????????
?????????????????
2. Cats eye chrysoberyl
3. Alexandrite ??????????????????????? cats
eye alexandrite ???????????????
fluorescence light
incandescence light
incandescence light
fluorescence light
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Crystallography
Orthorhombic ??????????????????? ????????
trilling
Physical properties
Cleavage ??????????????? prismatic
Fracture ?????????
Hardness 8.5
S.G. 3.73 (0.02)
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Optical properties
Luster vitreous - subadamantine
Colour yellow to greenish yellow ,
brownish yellow to brown
Transparency transparent to translucent
Optic character Bi
Birefringence 0.008 - 0.010
Dispersion 0.015
Fluorescence chrysoberyl ???????????
alexandrite ????????????????????? ?????????? ??
LWUV ??? SWUV
Absorption spectrum chrysoberyl
????????????????????????????? 440 nm.
alexandrite ??????????????????????????????
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Chemical properties
Chemical formula BeAl2O4
Group oxide
chrysoberyl ????????????????? peridot ???????
hexagonal closed packing
????? chrysoberyl ??????? Fe3
??????????????????? alexandrite ??????? Cr3
Occurrence
??????? granite pegmatite ??? mica schist
?????????? ??? Brazil Sri Lanka Madagascar
???????? Ural Myanmar Zimbabwe ???
Zambia
Name
Chrysoberyl ??????? golden beryl
Cymophane ??????? wavy light
Alexandrite ????????? ??????? Czar Alexander
II ??????????
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Diagnostic features
chrysoberyl ??????????????????????????????????
????????????????? ????
olivine
greenish yellow beryl
colour change garnet
cats eye quartz
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4.5 ?????? (Spinel)
???????????????????? ??? Magnesium Spinel (Mg
Spinel)
The Timur Ruby
The Black Princes Ruby
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Crystallography
???? isometric octahedron
?????????????????? (spinel twin)
Physical properties
Cleavage ??????????????????
Fracture ?????????
Hardness 8
S.G. 3.60 (0.10 ??? - 0.03)
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Optical properties
Luster vitreous - subadamantine
Transparency transparent to opaque
Optic character isotropic
Dispersion 0.020
R.I. 1.718 ( 0.017 ??? - 0.008)
Fluorescence spinel ????? ???? ??????
??????????????????????????? ??
LWUV ??????????????????????????????? ??????
SWUV ??????????????????????????
Absorption spectrum
red pink and orange spinel
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Colour
Spinel ???????? ????????? ??? red pink
orange blue purple black
pink
purple
orange
red
blue
colour-change spinel
black star spinel
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Chemical properties
Chemical formula MgAl2O4
Group spinel
Diagnostic features
rubellite
ruby
garnet
Occurrence ??????????????????????????????????
??????????????????? placer ???????????????????
corundum ???? Myanmar Thailand Sri Lanka
Tanzania
Name ????? spinel ?????????????
spark ?????? ????????
????????????????????? spina ?????? ????
?????????
44
4.6 ??????? (Garnet)
Crystallography
???? isometric dodecahedron trapezohedron
???????? 2 ???????????
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Physical properties
Cleavage ??????????????????
Fracture ????????????????????????????? ????
hydrogrossular ??????????????
Hardness 6.5 - 7.5 ?????????????????????
???????
S.G. 3.15 - 4.30
????????????????????????????
Optical properties
Luster vitreous - subadamantine
Colour ???????? ???????????????????????????
?
Transparency translucent-semitranslucent
???? hydrogrossular --gt transparent to
opaque
Optic character isotropic ???????
anomalous double refraction
R.I. 1.720 - 1.880
????????????????????????????
Dispersion 0.024 - 0.057
????????????????????????????
Fluorescence ???????????????????
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Chemical properties
Garnet ??????? silicate ??????????
?????????????? ??? A3B2SiO4
A ?????????????? 2
B ?????????????? 3
Garnet ??????????? 2 ???(series) ???
1. Pyralspite series ?? B ???? Al 3
2. Ugrandite series ?? A ???? Ca 2
???????????? garnet
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Garnet ??????(species) ????? ????? pyralspite
?????? Ugrandite
Garnet ?????????????????????????????????????????
??????? ??????? 2 species ?????????????????????
?????????????????? ????????
48
4.6.1 ????? (Pyrope)
?? Fe ??? Cr ?????????? Mg -----gt
????????????? ?????? ?????????
S.G. 3.78 (0.09 ??? - 0.16)
Hardness 7 - 7.5
R.I. 1.740 (0.002 ??? - 0.026)
Dispersion 0.024
Fluorescence ???????????
Absorption spectrum
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????????(rhodolite)

• ???? garnet ????????????? pyrope ???
  almandine

• ????????????? ?????????

• ????????????? ??????????? pyrope ???
  almandine

Hardness 7 - 7.5
R.I. 1.760 (0.010 ??? - 0.020)
Dispersion 0.026
Fluorescence ???????????
Absorption spectrum ?????? almandine
Pyrope ????????? ultrabasic ????
peridotite kimberlite(?????????????)
?????????? ??? Czechoslovakia ????????????
Bohemia ???????? Bohemian garnet
Rhodolite ????????? eclogite
?????????????????????? ??? Sri Lanka India
Tanzania ??? Zimbabwe
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4.6.2 ????????? (Almandine)
Almandine ????????? ????????????????
Fe3Al2Si3O12 --gt ???????????????
Almandine ???????????????????????????????????
almandine ??? pyrope
???? ???????? ???????????(carbuncle)
??????????????? ??? ??????????? ??? ??????????
Hardness 7 - 7.5
S.G. 4.05 (0.25 ??? - 0.12)
Dispersion 0.024
Fluorescence ???????????
Absorption spectrum
Occurrence ???????????????????? regional
metamorphism ?????????? ??? ???
Idaho ??? India ???????????????? 4 ???? 6 ??
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4.6.3 ??????????? (Spessartine)

• ?????? ???? ??????????? ??? ???????? ?????
  ??????? Mn

Hardness 7 - 7.5
R.I. 1.810 ( 0.004 ??? - 0.020)
Dispersion 0.027
Fluorescence ???????????
Absorption spectrum
Occurrence ???????????????????? contact
metamorphism ???????????? ????????????
Mn ???? rhodonite ?????????? ??? Myanmar
Sri Lanka Madagascar Brazil ??? USA.
52
Garnet ???????????????????????????? pyrope ???
spessartine ?? 2 ???? ???
(Mg,Mn)3Al2(SiO4)3
1. ????????(Malaia) ???????????? ????? ??????
???????? spessatine ??? hessonite
2. ????????????????
(Colour-change garnet)
Hardness 7 - 7.5
S.G. 3.81 ( 0.04 ??? - 0.03)
R.I. 1.760 ( 0.020 ??? - 0.018)
Fluorescence ???????????
Absorption spectrum ??????????????????????????
? 410 420 ??? 430 nm.
???????????? spessatine
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4.6.4 ???????????? (Grossularite)
Hessonite ????????-??? ??? ???-?????? ???????
Mn ??? Fe
Tsavorite ??????? ??????? V
Pink grossularite ????????????? Fe
Hydrogrossular ?? OH ???????????????
??????? ????????????????? ???? ??? ??????
54
S.G. 3.47 ( 0.08 ??? - 0.32)
Hardness 7
R.I. 1.720 (0.010 ??? - 0.050)
Fluorescence ???????????
Absorption spectrum ??????????????????????????
???????????? 400 - 460 nm. ??????
?????????? 463 nm.
green grossularite
hessonite
Occurrence ??????????????????????????????????
?
????? hessonite ???????? ??? Sri Lanka ???
Canada
????? tsavorite ??????????? ??? ???????? Tsavo
????? pink grossularite ??? Mexico ??? South
Africa
55
4.6.5 ?????????? (Andradite)

• ???? garnet ???????? ??? ????? ?????? ?????

• ?????????????????? ??????? ????????????????
  ???????? ??????????(Demantoid)

• ????????? ??????? Cr ?????????? Fe
  ?????????????

• ??????????????????????????

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Hardness 6.5 - 7
R.I. 1.888 (0.007 ??? - 0.003)
Dispersion 0.057
Fluorescence ???????????
??????????????
Absorption spectrum ??????????????????????????
400 nm.
Occurrence ????????????? demantoid
??????????????? Ural ?? USSR
????? Piemont ?? Italy ???????? Zermatt ??
Switzerland
????????? ???????? California
?????????? (Uvarovite)
???? garnet ??????? ????????
????????????????????? ???????????????????
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Name
????? garnet ?????????????? granutus ??????
???? (grain)
????? pyrope ????????????? ?????? ????????
????? rhodolite ????????????? rhodon
?????? ??????
????? almandine ?????????????? Alabanda
????????????????? garnet
????? spessartine ?????????????? Spessart
?? Bavaria ?????? spessartine ????????????
????? malaia ????????? Buntu ??????
??????
????? grossularite ????????? gooseberry
???????????????????????????
????? hessonite ????????????? ??????
???????????
????? andradite ??????????????????????????
???? ???? d Andrada
????? demantoid ??????????????????????????
?????????
58
Garnet group
Species
Variety
Variety
pyrope
rhodolite
malaia
almandine
colour-change
spessartine
hessonite
tsavorite
grossularite
hydrogrossularite
andradite
demantoid
uvarovite