Quartz with Pyrite
Quartz is the second most abundant mineral on Earth, present in many different types of rocks. Although usually clear or milky white in colour, quartz is found in a variety of colours due to impurities in the crystal structure. Pure quartz consists of silicon and oxygen only, but atoms of other elements often make their way into the quartz crystal structure, colouring the crystals. Some varieties of quartz, like purple amethyst and yellow citrine, are considered to be semi-precious gemstones and have been used since ancient times to make jewellery and decorative objects. Well-formed (euhedral) crystals of quartz have a hexagonal cross section and are highly collectible.
Pyrite is a common iron sulphide mineral found in many different geological settings. It has a brassy-yellow metallic colour that has caused many people to mistake it for gold, giving it its other name, “Fool’s gold”. Pyrite and gold can be quite easily distinguished from one another: pyrite is less yellow and much lighter and harder than gold, which can be scratched with a pocket knife. Pyrite often forms perfect cubes, which can grow to quite large sizes, because of its crystal structure. The word pyrite comes from the Greek word ‘pyr’ meaning fire, because it will spark if hit with other metal or stone objects.
This beautiful specimen of quartz comes from the Cariboo Gold Quartz mine, near Wells in the Cariboo region of BC. The area is famous for its gold rush of the 1860s and is still being worked and explored today.
Gold-bearing quartz veins were noted and developed from the 1870s onwards on several claims owned by the mine, including the Cariboo claim and later the Pinkerton and Rainbow claims. The Cariboo Gold Quartz Mining Co. Ltd. was founded in 1927 by prospector Fred M. Wells, who established the town of the same name. The company mined quartz veins on Cow Mountain, just west of Wells. The area is being developed again today by Barkeville Gold Mines. The Cariboo Gold Quartz mine was most active from 1933 to 1959, when it is reported to have produced 1.68 million tonnes grading 0.37 ounces per tonne gold (621,000 total ounces of gold).
This sample is typical of the veins mined on the claims. Well-formed “euhedral” quartz crystals with fine grains of silver-yellow pyrite develop in veins that also contain gold, either as free visible gold or as very fine gold in the pyrite.
Store: Association for Mineral Exploration (AME)
Accession #: AME 656
Primary Mineral: Gold
Secondary Mineral: Pyrite
Site Locality: Cariboo Gold Quartz Mine
Location: Wells, British Columbia
Special Features: n/a