Antimony: Lesser Known, Yet Highly Critical

Despite its designation as a critical mineral in the US, Canada, Australia and the EU, antimony remains largely unknown.

Although it may seem less popular than its hyped-up counterparts like rare earths and lithium, antimony’s industrial and strategic importance cannot be ignored. Antimony has for decades been crucial to countless sectors, and its military applications made US-produced antimony crucial to the Second World War.

Now, as the world moves towards a future defined by clean energy and decarbonization, it’s arguably more important than ever — and a compelling addition to any investment portfolio.

Antimony: An overview

A silvery-blue metalloid element, antimony is primarily found in the mineral ore known as stibnite — a steel-gray sulfide that largely forms in hydrothermal deposits alongside gneiss, limestone and granite. In addition to stibnite, the element also occurs in over a hundred different minerals, including kermesite, argentiferous tetrahedrite, jamesonite and livingstonite. Although it is brittle and flaky, antimony is regarded for its strengthening and hardening capabilities as an alloying agent.

Antimony has a history that spans millennia. There are historical records of multiple civilizations using the element in both its metallic and sulfide form for everything from pottery to medical remedies and makeup. Records from the 15th century also indicate that antimony was used in various alchemical practises, as well as in alloys for products such as mirrors and bells.

Yet for all its applications, antimony was not generally regarded as a critical strategic resource until sometime around the 1900s. That is when the element began being used in a range of different military applications, owing to its role in the creation of tungsten steel and as a hardening agent for lead. Military applications antimony is used for today include precision optics, night-vision goggles, armor-piercing rounds, explosives, hardened lead, ammunition primers, infrared sensors, military clothing, communications equipment and even nuclear weaponry.

The US was initially reliant on China for antimony. However, the outbreak of the Second World War saw US supply of antimony cut off by Japan. Fortunately, a stibnite mine in Central Idaho was able to cover the supply shortage, fulfilling roughly 90 percent of America’s antimony requirements and producing roughly 40 percent of the required tungsten steel. Unfortunately, that mine ceased operations in 1997.

Today, China maintains a stranglehold on global antimony supply, processing nearly 80 percent of all antimony resources — despite a steadily declining share of global production.

Antimony’s role in electrification

In addition to its military applications, antimony is also required to manufacture semiconductors, electric switches, fluorescent lighting, high-quality clear glass and lithium-ion batteries. Without antimony, the majority of modern technology would be impossible to produce.

This applies equally to cleantech and renewable energy. Antimony is a key element in the production of solar panels and wind turbines. Moreover, the mineral is integral to the development and production of liquid metal batteries, which look to be a reliable, safe alternative for battery power storage.

This is best exemplified by the Ambri battery platform. Backed by Microsoft (NASDAQ:MSFT) founder Bill Gates, the modular, containerized DC system consists of a series of high-capacity battery cells assembled into trays within an insulated and self-heating thermal enclosure. The cells make use of calcium, antimony and calcium chloride. This means that they are not only more affordable than traditional lithium-ion batteries, but are also considerably more reliable, capable of enduring tens of thousands of cycles, all while maintaining a 20 year lifespan. Ambri’s fully recyclable batteries are also tolerant of both overcharging and undercharging, and they are immune to thermal runaway, electrolyte decomposition and off-gassing.

Shoring up supplies

As is the case for other critical minerals, reliance on countries such as Russia and China for antimony production is a risky prospect at best. China has, on multiple occasions, shown the propensity to wield its market dominance as a political weapon, while trade with Russia has taken a big hit following its unprovoked invasion of Ukraine.

Unfortunately, antimony is currently only mined in a few countries. According to the US Geological Survey, China accounted for 54.5 percent of total antimony production in 2022, followed by Russia at 18.2 percent and Tajikistan at 15.5 percent. Fortunately, this may soon change.

In addition to occurring in hydrothermal deposits, stibnite is also frequently found alongside high-grade gold. New Zealand-based mining and exploration company Siren Gold (ASX:SNG) is incredibly well positioned in this regard. The company maintains multiple projects on the Lachlan Fold Belt — the same orogenic belt that hosts the Costerfield mine, the largest producer of stibnite, and thus antimony, in Australia.

Siren’s Auld Creek prospect is particularly promising, displaying very similar mineralization to Costerfield. Gold-antimony mineralization extends from Auld Creek through two of Siren’s other permits, Big River and Cumberland. The Reefton goldfield asset in New Zealand, on the other hand, is the site of significant historic mining and is believed to contain extensive reserves of both gold and stibnite.

“Australia produces roughly 5 percent of the world’s antimony,’ explained Siren Gold Managing Director Brian Rodan. ‘Siren, with appropriate development funding, could potentially produce up to 20 percent of the world’s antimony from its Reefton project.’

Siren Gold is not the only mining company setting its sights on stibnite. Molten Metals (CSE:MOLT) primarily targets past-producing antimony and tin resources. It currently maintains antimony projects in Slovakia and Canada.

Other players include Anchor Resources with its fully owned Bielsdown project in New South Wales, and Perpetua Resources (TSX:PPTA,NASDAQ:PPTA) with its Stibnite gold project, which has the distinction of housing one of the largest-known economic reserves of antimony.


Although antimony may not receive as much coverage as other more popular critical minerals, it’s no less important. Already essential to multiple applications within the technology and military sectors, antimony has only grown progressively more important with the transition to a cleaner, more sustainable future. Mining companies around the world are working to meet the ever-increasing demand for the mineral — and each of these companies represents a new investment opportunity.

The information contained here is for information purposes only and is not to be construed as an offer or solicitation for the sale or purchase of securities. Readers should conduct their own research for all information publicly available concerning the company. Prior to making any investment decision, it is recommended that readers consult directly with Siren Gold and seek advice from a qualified investment advisor.

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