What is Jade?
| Jade is a commercial term
encompassing green, white, black or yellow-brown jadeite and nephrite. Jadeitite is a rock
that consists essentially of jadeite (sodium-rich, high-pressure pyroxene), whereas
nephrite consists of prismatic to acicular amphiboles of the tremolite-actinolite series
forming bundles that are randomly oriented and interlocked. All of the known jade deposits
in B.C. are of the nephrite variety. Jade has been
used since Neolithic times for jewelry and tool making. Today, the best material is used
as gemstones. Large quantities are used for carving and ornamental stone or for table
tops. Industrial grade material is used for tile making. |
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Geology and Origin
Nephrite occurs at over fifty sites in B.C. in bedrock,
boulder fields and talus. The bedrock occurrences are typically lens shaped and occur at
or near contacts of mafic-ultramafic rocks (mainly serpentinite) with metasedimentary or
igneous felsic rocks.
Nephrite formed by metasomatic exchange between ultramafic
and silica-bearing rocks within the Mississippian to Jurassic age oceanic Cache Creek and
Slide Mountain terranes of B.C.
High pressure blueschist or eclogite grade metamorphic
rocks, favourable for jadeitite exploration, are found in the Bridge River, Pinchi Lake,
Dease Lake and Jennings River areas of B.C.
Known jade mineral occurrences are documented in the B.C.
Geological Survey Branch's MINFILE database which is available on the Ministry's website
at www.em.gov.bc.ca/mining/geolsurv/minfile
Click to view the Jade in B.C. Map
Ornamental and Gemstone Market
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The world jade market is
estimated at 300 tonnes per year, with three quarters of this originating in B.C. The
price of raw jade varies from less than $10 to $100 per kilogram depending on quality and
quantity. The best B.C. nephrite is bought by local
artists and transformed into artwork which is in demand internationally. The largest
sculpture made of B.C. nephrite is probably the Buddha commissioned for the Wat
Dhammongkol Monastery in Bangkok. It was carved from a 32 tonne nephrite boulder. This
transaction was worth about $350,000 to the Jade West Group of Companies. |
Dimension Stone
Industrial grade jade has been stockpiled in B.C. in
anticipation of serving the growing natural-stone tile market. Jade tiles have great
market potential in new, upscale residential and commercial building applications.
Jade sampling, Cry Lake area
Prospecting Tips
- Most nephrite deposits occur along or near the contacts
between ultramafic and metasedimentary rocks.
- In situ deposits may be marked by downslope, down ice, or
downstream accumulation of nephrite boulders. Follow-up of nephrite boulder trains and
fans is a good prospecting method.
- Nephrite boulders have a rough, either buff, brown, gray or
white weathering surface, which renders nephrite difficult to identify. A hammer blow to a
nephrite boulder leaves little or no mark and the hammer springs back with unexpected
intensity due to its toughness.
- Large boulders may be test drilled or sawn to identify those
with economic promise.
- Rodingite (white rock) in bedrock or boulders may indicate
favourable geological conditions for nephrite.
Jade boulder from the Kutcho Creek deposit,
with Kirk Makepeace, Jade West Group of Companies
For information about Jade in B.C., contact the Industrial Minerals Geologist of the
Geological Survey Branch, Energy and Minerals Division.
Selected Bibliography
Leaming, S.F. 1995, Jade in North America, in Roger Keverne,
editor; Jade: Annes Publishing Limited, London; p. 298-315.
Leaming, S.F. 1978, Jade in Canada; Geological Survey of Canada, Paper 78-19, 59p.
Leedham, T.,1999: Working with Jade; Newsletter, v.18, no.1, Gem and Mineral Federation
of Canada, p. 8-9.
Scott, A.,1996, Jade a Mystical Mineral; Equinox, No.89, p. 64-69.
Simandl, G.J. and Gunning D.F. 2000: Dimension and Ornamental Stone in British
Columbia; in Natural Stone in Canada, Roc Magnina, p. 47-51.
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