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Emeralds from China
Vincent Pardieu GIA Laboratory Bangkok Dan
Marshall Simon Fraser University
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Emeralds from China Part 1 Geology of
Emeralds from Yunnan and Xin Jiang.Part 2 A
visit to Davdarand gemology of Davdar emeralds.
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Chinese Emerald
Dyakou and Davdar occurrences
Background Beryl Emerald Current models of
emerald formation? Geology / tectonic setting /
mapping 40Ar/39Ar geochronolgy Fluid inclusions,
SEM Cathode Luminescence Stable isotopes
sourcing / thermometry Preliminary conclusions
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Emerald Localities
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after
Emerald deposits Type I - Igneous Related (Most
common)
Igneous Related, with schist
Igneous Related No schist
after Schwarz et al. (2002)
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Emerald deposits Type II - Schist Related
Schist related no intrusions
Muzo type
after Schwarz et al. (2002)
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Emeralds in China
Davdar, Xin Jiang
Dyakou
Davdar

• Occur in very different geology, but both
  areclose to granitic rocks.

Dyakou, Yunnan
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Tectonic Map of China
Dyakou, Yunnan

• Tectonic Zone 48 South China Fold Belt
• Structurally deformed - very old rocks
  - intruded by younger 80 Ma granitic
  rocks

Davdar, Xin Jiang

• Tectonic Zone 23 Kunlunshan Fold Belt
• Foreland Fold Thrust - Pleistocene and
  Paleozoic strata

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Emeralds in China
Dyakou, Yunnan
Davdar Xin Jiang

• Quartz and carbonate veins
• Sedimentary host rocks
• Low temperature
• Not pegmatite veins

• Quartz and pegmatite veins
• Metamorphic host rocks
• Medium temperature
• clear association with granite

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Emerald in China Ages
Dyakou, Yunnan
Davdar, Xin Jiang
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Stable Isotopes
after Giuliani et al. (1998)
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Fluid Inclusions
Dyakou (2 phases liquid vapor)
Davdar (3 phases liquid vapor halite)
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Emeralds in China Geological Summary
Davdar
Dyakou

• Temperature Low 300 - 325 C
• Age Tertiary (10 to 35 Ma)
• H2O-CO2 -CH4 -N2 (high salinity) fluids
• Cr / V dominant emerald chemistry
• dD / d18O values (extended magmatic)
• Mica alteration haloes
• No clear granite association
• Paleozoic host rocks
• Less deformed / less metamorphosed host
• Unidentified Cr, Be and V source rocks
• Tourmaline present in alteration halo
• Emerald deposit type unknown?

• Temperature Medium 350 400 C
• Age Cretaceous (120 Ma)
• H2O-CO2 -CH4 -N2 (low salinity) fluids
• V dominant emerald chemistry
• dD / d18O values (extended magmatic, but
  different)
• Mica alteration haloes
• Associated with nearby granite / pegmatite
• Paleozoic host rocks
• Deformed / metamorphosed host rocks
• Unidentified Cr, Be and V source rocks
• Tourmaline present in alteration halo
• Emerald deposit type Igneous associated

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Emeralds from China Part 1 Geology of
Emeralds from Yunnan and Xin Jiang.Part 2 A
visit to Davdarand gemology of Davdar emeralds
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June 2006 Peshawar and Mingora gem markets,
Pakistan
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Satellite view over the Davdar mining area
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I I I I I I I I
Mine 01
Mine 02
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2 mining companies work the area . The Junling
Cie (from Shenzen) . Miss Ji (Beijing) with a
Pakistani partner
Mine 01
Mine 02
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Mine 01
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Mine 02
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Emeralds seen on site at Davdar visiting mine 01
and 02
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Emeralds seen on site at in Peshawar gem market
(Pakistan)
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Emeralds seen on site at Tashkurgan gem market
(Xin Jiang)
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Brief gemological properties of 10 Emeralds from
Davdar, Xin Jiang, China
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Brief gemological properties of 10 Emeralds from
Davdar, Xin Jiang, China
Color Green to Bluish Green Refractive Index
1,578 to 1,584 and 1,585 to 1,593Birefringence
0,007 to 0,009Specific Gravity 2,68 to 2,74
Chealsea Filter two stones out of ten had a
red reaction, others were inert to brownish.SWUV
(Short Wave Ultra violet) Brownish to red.LWUV
(Long Wave Ultra Violet) Inert to
brownish. Chemistry Cr mainly but the stones
studied contain also vanadium and
iron. Inclusions All the 10 stones studied were
presenting some multiphase phases inclusions
(three phases minimum) but the shape of these
inclusions was slightly different from the well
known "jagged" design seen in many emeralds from
Colombia and some emeralds from Panjshir valley.
Several emeralds had also some whitish
transparent crystals as inclusions.
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UV Vis
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Conclusions This study shows that potentially
using EDXRF, UV-Vis, and studying the
emerald inclusions, it seems possible, in most
cases, for experienced gemologists to separate
emeralds from Davdar from gems from other sources
using standard Gemological Laboratory equipment.
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Finally, what is it all for?
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To provide better reports
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Thanks for participating to this adventure.