The Geological Society of Hong Kong 香港地質學會
Last updated: 03 September 2010
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Mineral of the month

Rock of the month

[ Topaz ]
Topaz is a mineral with chemical formula Al2SiO4 (F, OH)2. It has vitreous luster, and occurs in various colours including yellow, orange, blue, pink, green and colourless, while the streak is white. Topaz has orthorhombic crystal system and usually forms columnar crystals, and its hardness is 8. Topaz is usually produced in pegmatite, geode and hydrothermal W-Sn quartz vein during late stage magma differentiation of granite. Small amount of topaz can be found in quartz veins at San Shek Wan, Hong Kong. Topaz is suitable for producing jewellery because of its high hardness, clear transparency and rich of colours. The colour of topaz changes to blue after irradiation treatment.
 


Our Society - GSHK
The Geological Society of Hong Kong is a non-profit organisation that attempts to promote geological and earth science studies within Hong Kong and the adjacent region. We organise local and overseas fieldtrips, as well as lectures. The Society publishes a journal (The Hong Kong Geologist) and bulletins dealing with a variety of earth science subjects.




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Whats New!

Coming Events:

Boat Trip from Ma Liu Shui to Tsim Sha Tsui Talk

Date: Sept. 18 2010
(Saturday)

Training Course Talk
Geology for Geo-tourism in Hong Kong
Date: 22 Sept. ~ 03 Nov. 2010

GSHK Workshop (Members only)
(Close application with excellent overbooking)

An Introduction to Rocks - 3 lectures
Lecture 1: 23rd June 2010 (Wed)  Basic of Igneous Rocks
Lecture 2: 7th July 2010 (Wed)   Basic of Sedimentary Rocks
Lecture 3: 13th July 2010 (Tue)  Basics of Metamorphic Rocks, and PolyU Geo-Lab Visit
Lecturer: Mr. C M Lee (in Chinese)
Time: 7:00 - 8:30 pm
Venue: PolyU      TU432
Deadline: 20th June 2010

Max. 20 nos. of participants; for members only and priority to applicants for all three dates
Talk Professional Branch article : A Close encounter of volcanic tuff/granite contact at Anderson Road Quarry

1984-1997 Second collection of HK Geotechnical papers

1995-2002 Hong Kong Geologist

Geologists Articles

Fieldtrip reports by members

Fieldtrip photos

Recent Activities Albums :

Professional Branch Taiwan Marble mine visit 28-05-2009

Conference on Geological Science and Geological Engineering, 18-19 SEP 09 Shenzhen

Professional Branch seminar photo on 25-09-2009

North Xinjiang 16 days field trip 2009-07-18~ 08-02

Tungpingchau Geo-guide trip 2009-11-07

Shalowan Garnet and topaz searching 2009-12-20

Wu Kai Sha Tsui - ShaTin Granite on 27-02-2010

Zhanjiang (Guangdong) 6 days excrusion 01~06-04-2010
Talk