Information Circular 1987-5
Identification of Common Rocks
The Identification of Common Rocks by Eileen Van der Flier-Keller and William J. McMillan was originally produced as Information Circular 1987-5 by the BC Geological Survey of the B.C. Ministry of Energy and Mines. This publication is now out-of-print and is only available from this website.
PDF version (PDF document, 2.2 MB)
The Identification of Common Rocks, Ministry of Energy, Transport and Communications, 1980.
The entire earth's surface is made up of rocks. Although in many places the rocks are covered with river, wind or glacially deposited materials, there are few places in British Columbia where rocks cannot be found. A large number of different rock types exist. The identification of common rocks may, however, be complicated by the fact that certain rock types grade into each other. For example, there is every gradation between a shale and a sandstone - including sandy shale and shaly sandstone, and also between granite and gabbro. In addition, a single rock type may vary in appearance.
These pages deal mainly with rock types found in British Columbia. However, the rocks of this province are not unique and the principles used here can be applied anywhere. The geology of British Columbia is fascinating; it is complex, many processes are at work, and there are a great variety of rocks. Rocks are an integral part of the landscape; being able to identify them can greatly enhance your enjoyment of the natural world.
Before starting to identify rocks it is helpful to know a little about:
Rocks are precisely classified using various properties which are determined by petrologists using microscopes and other complicated and sophisticated laboratory equipment. However, more approximate "field" terms are used by geologists to identify rocks in outcrop. These terms can be easily used by non-specialists using simple techniques which can be applied in the field or at home. The methods used assume little prior knowledge and the equipment required is limited to:
- a rock hammer to break off pieces of rock
(Warning - do not use a carpenter's hammer,
they are hardened steel and will chip.)
- a hand lens or magnifying glass with 6 to 10 power magnification
- a dropper bottle of dilute hydrochloric acid
(5 parts of concentrated acid in 100 parts of water)
These are all obtainable at modest cost from rockhound stores or geological supply companies.
These pages deal only with identifying common rocks, and as such do not dwell on the geology of the rocks or where and how they occur. Those who wish to pursue further study should consult any of the excellent introductory textbooks and field handbooks that are available in bookstores and libraries.
Note: Certain terms used in these pages may be unfamiliar to the non-geologist. They have been hyperlinked to a glossary where a short definition can be found.
All printed publications of the BC Geological Survey are available digitally, free of charge, from this website.
For questions or more information on geology and minerals in British Columbia contact BCGS Mailbox or call toll free (BC Residents only).