Chalcopyrite Pyrrhotite Sphalerite

Specimen Summary

This specimen contains several common sulphide minerals, including the economically important ore minerals chalcopyrite (copper sulphide) and sphalerite (zinc sulphide). These minerals are the principal sources of copper and zinc used in everything from electrical wiring and renewable energy technologies to galvanized steel and batteries. The third sulphide mineral present is pyrrhotite, an iron sulphide that ranges in colour from bronze to dark brown or black with a metallic lustre. Unlike chalcopyrite and sphalerite, pyrrhotite is not typically mined for its iron, as iron is much more economically obtained from iron oxide minerals such as hematite and magnetite. However, pyrrhotite is an important mineral in many ore deposits because it can host or occur alongside valuable metals such as gold, silver, copper, nickel and platinum-group elements. One of pyrrhotite's most distinctive characteristics is its variable magnetism. Unlike most sulphide minerals, pyrrhotite can be weakly to strongly magnetic depending on its exact chemical composition. This occurs because the mineral contains varying amounts of iron, with slight deficiencies in its crystal structure producing stronger magnetic properties. Geologists often use this characteristic to help identify pyrrhotite in the field and to detect buried sulphide-rich rocks using airborne or ground-based magnetic surveys. Pyrrhotite commonly occurs in mafic and ultramafic igneous rocks, where it is frequently associated with pentlandite, the world's primary nickel ore mineral. It is also found in many volcanic-hosted massive sulphide (VHMS), magmatic nickel-copper, and gold-bearing hydrothermal deposits, making it an important indicator mineral during mineral exploration. This specimen comes from the North Rock Mine near Fort Frances, Ontario. The property was discovered by prospectors in 1958, with underground mining commencing in 1972 via a vertical shaft. The area is underlain by a variety of mafic and ultramafic rocks, including well-preserved basaltic pillow lavas—distinctive volcanic rocks that formed when molten lava erupted underwater and cooled rapidly. These rocks provide important evidence of Ontario's ancient volcanic history and the geological processes that created the sulphide mineralization found on the property.

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-158

Virtual Museum ID:

19-AME158

Accessibility:

Date Added to VM:

2018-02-15

Location Information

Sample Origin:

Fort Frances, Rainy River District, Ontario

Specific Site:

North Rock Mine

UTM Easting:

470754.8343

UTM Northing:

5384337.719

Datum:

15 (NAD 83)

Coordinate Accuracy:

Approximate

Specimen Details

VM Category:

Mineral

Primary Features:

Chalcopyrite Pyrrhotite Sphalerite

Primary Mineral Formula:

CuFeS2, (Zn,Fe)S, Fe(1-x)S

Primary Category:

sulphide

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:

N/A

Geological Period:

N/A

Stratigraphic Age:

N/A

Geological Belt:

N/A

Geological Terrane:

N/A

Minfile ID:

N/A

Minfile Link:

N/A

Site Details:

N/A

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