Iron, Lead, Silver & Zinc
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 the 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.
Galena is the main ore mineral for lead. Because of its relatively low melting temperature it can be easily smelted and has been used as a source of lead since ancient times. Galena has a cubic crystal system and can often be found as cubes or octahedra. Its shiny grey metallic lustre and heavy, dense nature make it easy to recognize. Galena often contains small amounts of silver, which add to its economic value.
Sphalerite is the main ore mineral for zinc, and although relatively common, finding it in commercial amounts is somewhat rarer. The zinc will give the mineral a yellow or red hue, but iron can replace the zinc in the atomic structure, making the crystals black. Rarely, cobalt finds its way into the structure, and produces green crystals. Although sphalerite is a relatively soft mineral, it can be cut (faceted) into attractive gems, which are used for mineral displays.
This sample is from the Nahwitti Lake area west of Port Hardy at the northern end of Vancouver Island. It contains fine-grained pyrite, sphalerite and galena with minor amounts of silver in galena.
The mineral occurrences around Nahwitti Lake are generally 1-2 m long pods of sulphides. They formed when hot fluids were circulated around small magma bodies that intruded the host Quatsino limestone, altering and silicifying the rock.
Prospectors and geologists have explored the area for lead, zinc and copper mineralization but so far, no one has located significant deposits.
Store: Association for Mineral Exploration (AME)
Accession #: AME 941
Primary Mineral: Iron, Lead, SIlver & Zinc
Site Locality: Nahwitti Lake
Location: Port Hardy, Vancouver Island, British Columbia
Special Features: n/a