Iron Lead Silver Zinc

Specimen Summary

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.

Specimen Data

 

The information listed below relates to the current holding location or collection that the sample is from, and whether the item is viewable at that location or is part of a private collection. Coordinates are given as guides, and we remind you that collecting specimens from these locations is not allowed. Caution is advised visiting such sites and Below BC assumes no responsibility for any injuries or trespassing charges that may occur as a result of the viewer entering these sites.

Collection Details

Original Collection:

Association for Mineral Exploration (AME)

Sub Collection:

-

Collection ID:

AME-941

Virtual Museum ID:

19-AME941

Accessibility:

Date Added to VM:

2018-02-15

Location Information

Sample Origin:

Nahwitti Lake, Port Hardy, Vancouver Island, B.C.

Specific Site:

Giant Explorations Ltd.

UTM Easting:

584673

UTM Northing:

5616718

Datum:

09 (NAD 83)

Coordinate Accuracy:

Approximate

Specimen Details

VM Category:

Mineral

Primary Features:

Iron Lead Silver Zinc

Primary Mineral Formula:

Fe2, Pb, Ag, Zn

Primary Category:

native element

Secondary Features:

Advanced Geological Information

 

The following section provides geological data relating to the specimen or the site it was collected from, when available. Information has been obtained from various sources including private and government datasets but may not be up to date. Any geological time periods or ages listed often relate to the primary geology of the area, and may not be the actual date of an event such as mineral formation.

Geological Formation:

Vancouver Group (Karmutsen and Quatsino formations)

Geological Period:

Upper Triassic

Stratigraphic Age:

145 to 163.5 Million Years Ago

Geological Belt:

Insular

Geological Terrane:

Wrangell, Plutonic Rocks

Minfile ID:

092L 242

Minfile Link:

https://minfile.gov.bc.ca/Summary.aspx?minfilno=092L%20%20242

Site Details:

The area is underlain by northwest trending belts of Upper Triassic volcanics and sediments of the Vancouver Group (Karmutsen and Quatsino formations) and Lower Jurassic Bonanza Group volcanics and sediments. These rocks have been intruded by the Jurassic Island Plutonic Suite.

Locally, galena-sphalerite mineralization occurs as fracture- fillings and disseminations in sheared and/or silicified Quatsino Formation limestone near a contact with Karmutsen Formation ande- sites. Quartz diorite of the Island Plutonic Suite is nearby. Magnetite can also be present. Areas of the limestone are altered to skarn. Mineralization is exposed in outcrops and trenches over a distance of 135 metres. A chip sample collected across 2.1 metres in 1966 assayed 373.7 grams per tonne silver, 3.18 per cent lead and 4.97 per cent zinc (Assessment Report 870). A 1966 grab sample assayed 356.5 grams per tonne silver, 3.18 per cent lead, 3.34 per cent zinc, 0.17 per cent copper and 0.34 grams per tonne gold (Assessment Report 870).

A 2.1 metre chip sample collected in 1988 assayed 743.9 grams per tonne silver, 2.55 per cent lead, 3.92 per cent zinc, 0.21 per cent copper and 0.07 grams per tonne gold (Christopher, P.A., 1988).

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