???????? (Crystal system)

1
????? 2 ???????? ???????????????????????????????
??
(Crystal system, physical and optical
properties of gemstones)
???????? (Crystal system)
2
1. Isometric system
diamond
garnet
spinel
3
2. Tetragonal system
zircon
4
3. Orthorhombic system
topaz
cyclic twin
chrysoberyl
5
4. Monoclinic system
orthoclase
5. Triclinic system
microcline
6
6. Hexagonal system

• Hexagonal division

aquamarine
beryl
apatite
7
6. Hexagonal system

• Rhombohedral division

corundum
quartz
tourmaline
8
Physical properties of gemstones

• Cleavage

Perfect rhombohedron in calcite
Perfect octahedron in diamond
Poor pinacoid in beryl
Imperfect pismatic in diopside
9
Physical properties of gemstones

• Parting

Rhombohedral
pinacoid

• Fracture

10

• Hardness

Mohs scale of hardness
11
Physical properties of gemstones

• Toughness

Excellent(?????????)
Exceptional(???????????)
corundum
jadeite
Poor (?????????)
Good (?????????????)
rose quartz
topaz
12

• stability

??????????????????????????????
kunzite
yellow-brown topaz
?????????????????????????????????
pearl
coral
opal
malachite
13
?????????????????(specific gravity)
??? ?.?. ?????????????????????????????????????
?????????????????????????????????????????? ????
???? ?????????? ????????????????????????????? (C)
?????????
diamond ?.?. 3.52 ???????? 10
graphite ?.?. 2.23 ???????? 1.5
14
???????????? ?.?. ?????????
1. ???? Hydrostatic weighting
??? ?.?. ???????????????????????????
??. ????????????????? - ??.????????????
???? ???????????????????????????
??????????????????????????????????????
??????????? ?????????????? 5 ?????(1.00 ????)
???????????? 3.75 ?????(0.75
????)
??? ?.?. 5 4.00
5 - 3.75
15
???????????? ?.?. ?????????
2. ???? Specific gravity liquid
3.32 ????????? jadeite(3.34) ??????
nephrite(2.95) 3.05 ?????? tourmaline(3.32)????
????????? ???? topaz(3.53) 2.67 ?????? natural
emerald ??? systhetic emerald(2.65-2.68) 2.62
?????? chalcedony (2.60 ???) ??? quartz (2.66
??) 2.57 ?????? amazonite(2.56) ??? chalcedony
16
???????????????????????????? (electrical and
magnetic properties)

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

• piezoelectricity (pressure electricity)

quartz
tourmaline

• pyroelectricity (heat electricity) tourmaline

• magnetism magnetite

hematite ??? imitated hematite(hematine)
hematite
17
Optical properties of gemstones

• Luster

- ?????????? (adamantine)
- ?????????????? (subadamantine) ???? ?????
- ?????????? (vitreous) ??????????????????????????
?????
- ???????????? (greasy) ???? ???
18
- ????????????? (waxy) ???? ???????????
- ??????????? (resinous) ???? ?????
- ????????? (silky) ???? ???????? (tigers eye)
- ????????? (pearly) ???? ???, ???????
19
Optical properties of gemstones

• Transparency

• ??????? (transparent)

• ??????????? (semitransparent)

• ???????? (translucent)

• ???????????? (semitranslucent)

• ?????? (opaque)

20
Optical properties of gemstones

• Colour

Red 700 630 nm.
Green 550 490 nm.
Blue 490 440 nm.
Orange 630 590 nm.
Violet 440 400 nm.
Yellow 590 550 nm.
21
absorption spectra
diopside
diopside absorb ????????????
emerald
emerald absorb ?????????????
22
??????????????????????????
1. ??????? ion ???????????(chromophore ????
dispersed metal ion)
???????????? ?????? Ti V Cr Mn Fe
Co Ni Cu
????????? peridot ??????? Fe2
?????????? chrysoberyl ??????? Fe3
23
Allochromatic gemstone ????????????????????????
????????????????? ???????????????????????
24
Idiochromatic gemstones ???????????????????????
??????????? ?????????
peridot (FeMg)2SiO4
malachite Cu2CO3(OH)2
Almandine garnet Fe3Al2(SiO4)3
Dioptase CuSiO3.H2O
rhodochrosite MnCO3
25
2. ??????????? (colour center)
????????????????????? lattice

• hole colour center crystal lattice ?? e
  ?????

• electron colour center crystal lattice ?? e
  ??????

green diamond
purple fluorite
smoky quartz
26
?????????? (inclusions)
??????????????????? ?????????????????????
??????

• chalcedony ?? green blue ?????????? chrysocolla

• carnelian ???????????????? hematite ????????

• aventurine quartz ?? green ?????????? fuchsite
  (Cr muscovite)

27
?????????????????? ?????????????? ????

• tourmaline ????????????????????? ?????
  bicolour tourmaline

• tourmaline ????????? green ????????????????
  red ????? watermelon
  tourmaline

• amethyst ?????????????????-???????????

• sapphire ????????????????????-???????????

28
??????????????????????-?????????????????????(patte
rn) ????? ??????
malachite
agate
rhodochrosite
29
???????????????? ???????(Optical phenomena or
Sheen)
1. ???????????????(chatoyancy or cats eye)
??????????????????????????????????????????????????
?????????????? ????????????????? ????????
???????????
chrysoberyl
30
2. ?????? ????????????(tigers eye)
???? quartz ????????-?????? ???????????????????
???????? (crocidolite asbestose)
?????????????????????? fibrous ????
hawks eye
31
3. ????? ??????????(Asterism of star effect)
?????????????????????????????????????????
???????????????? 2 ?????? (4 ??) ???? garnet
???? 3 ??????( 6 ??) ???? quartz corundum(ruby
??? sapphire)
32
4. ???????????(Iridescence)
?????????????????????????????? ???????????????????
??????????????????????????????????????????????(thi
n film)
pearl(orient)
(iridescence)
(iridescence)
33
Play of colour ?? opal
34
Labradorescence ?? labradorite
Adularescence ?? moonstone
35
Colour change ???? Alexandrite effect
fluorescence light
incandescence light
alexandrite
cats eye alexandrite
36
??????????????? (Aventurescence)
??????????????????????????????????????????????????
????

• aventurine quartz ????????????????????
  fuchsite (??? mica)

• sunstone ?????????????? ???????????????????????
  ???????????????

aventurine feldspar
sunstone
37
????????????????????????????????????????(Optical
tests)
???????????(fluorescence) ?????????????????????
?????????????? ultraviolet
UV - lamp
diamond ??????????????????? SWUV
38
?????????????(Refractive index R.I. )
??? R.I. ??????????????????????????????????
??????????????????????????????
R.I. ??? spinel 1.715
R.I. ??? peridot 1.654 ??? 1.690
39
(No Transcript)
40
??????????????? (Dispersion)
??????????????????????????????????
????????????????????????????????
diamond ????? dispersion 0.044
ruby , sapphire ????? dispersion 0.018
41
??????????????????????????? (single and double
refraction)
Isotropic ????????????????????????????????
???????(???????? isometric)
Anisotropic ???????????????????????(vibrate)
???? 2 ???????????????(polarization)

• uniaxial ????????????????? vibrate ???? 2
  ????????? 1 ???

(???????? hexagonal corumdum quartz
tourmaline beryl)
(???????? tetragonal zircon)
Uni
Uni -
42
??? birefringence ?????????????????????????????
????????? 2 ???
corundum ????? R.I. 2 ??? ??? 1.762 ??? 1.770
????? birefringence ??????? ??? 0.008
topaz ????? R.I. 2 ??? ??? 1.619 ???
1.627
?????????????? birefringence ??? ???? zircon
0.059 peridot 0.036
?????????? doubling
43

• biaxial ????????????????? vibrate ???? 2
  ????????? 2 ???

(?????????? orthorhombic chrysoberyl peridot
topaz)
(?????????? monoclinic moonstone jadeite
nephrite kunzite)
(?????????? triclinic kyanite amazonite)
( bi )
???? chrysoberyl topaz peridot
( bi- )
???? amazonite moonstone nephrite
44
Polariscope
analyzer
polarizer
light source
?????? interference figure ??? uniaxial ???
biaxial
45
????? (Pleochroism)
??????????????????????????????????
??????????????????????? ???????????
dichroscope
???? tourmaline
?????? uniaxial ????????????? 2 ?? (dichroism)
?????? biaxial ????????????? 3 ?? (trichroism)
???? tanzanite
46
???????????????????????(Absorption spectrum)
hand held spectroscope
desk top spectroscope
47
spectrum ???????????(white light)
peridot (Fe)
emerald ( Cr )
Ruby ( Cr )
almandine garnet (Fe)
spessartine (Mn)
alexandrite ( Cr )