Allemontite (stibarsen)

This allemontite (stibarsen) sample comes from the Engineer Gold Mine near Atlin Lake, B.C. You may notice that the mineral has two different names and while both are accepted stibarsen is the official accepted name.

It is a mineral composed of Arsenic and Antimony and is white to reddish-grey, and it tarnishes to grey. This is one of the minerals that make it more difficult to process ore from mines because of Arsenic’s toxicity to living organisms. While some animals need trace amounts of arsenic in their diet, it is highly toxic in large amounts to most living organisms. When mining deposits that have high levels of Arsenic, mining companies must pay special attention to keeping it contained.

The Engineer Mine is in Northwest B.C. with in the vicinity of Atlin, B.C. It operated as an underground Gold mine that eventually turned into a fully serviced town. The first hint of Gold was discovered in 1899 by Swedish prospectors. Later on an engineer discovered visible Gold in quartz/calcite veins and staked the claims with the Engineer Mining Company. It was finally mined in 1924 after being transferred to a New York ownership group. Overall by 1952 over 5.5km of underground tunnels had been created at the mine site and almost 20,000 oz of gold had been recovered.

The Engineer Mine is known for its excellent visible Gold samples hosted in quartz-calcite-pyrite veins and hydrothermal breccias. It has excellent examples of high grade Gold and Silver mineralization.





Specimen Information

Store: Association for Mineral Exploration (AME)


Accession #: AME-42

Primary Mineral: Allemontite (Stibarsen)

Secondary Mineral:

Site Locality:  Engineer Gold Mine

Location: Atlin Lake, B.C.

Special Features: n/a

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