Qualla: Argyle Diamond Mine

Argyle Diamond Mine: Introduction

Sun, 29 Mar 2026 15:05:37 GMT

Photo credit Reise-Line, CC BY-SA 3.0. A geologist named Maureen Muggeridge was working a floodplain near Lake Argyle in 1979, following a trail of alluvial diamonds upstream, when she reached the headwaters of a small creek called Smoke Creek. What she found there — a volcanic pipe, unlike any commercially mined diamond source in the world — would become the Argyle diamond mine, one of the most extraordinary mining operations in history. The discovery took a decade to trace. It took another 40 years to exhaust.

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Image: Reise-Line | CC BY-SA 3.0

Argyle Diamond Mine: A Different Kind of Pipe

Sun, 29 Mar 2026 15:05:37 GMT

Photo credit Brian W. Schaller, FAL. Most diamond mines in the world exploit kimberlite pipes — the geological formation long associated with diamond-bearing rock. Argyle was something different: a lamproite pipe, a much rarer type of volcanic structure. The Argyle pipe, formally designated AK-1, was composed of oli...

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Image: Brian W. Schaller | FAL

Argyle Diamond Mine: The Pink Diamond Problem

Sun, 29 Mar 2026 15:05:37 GMT

Photo credit Brian W. Schaller, FAL. Most of what Argyle produced was not particularly valuable. Eighty percent of its diamonds were brown — difficult to sell, requiring an entire marketing campaign by Rio Tinto to rebrand them as 'champagne' and 'cognac' tones. Only 5% of the mine's output reached gem quality, well...

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Image: Brian W. Schaller | FAL

Argyle Diamond Mine: Scale and Scope

Sun, 29 Mar 2026 15:05:37 GMT

Photo credit W. Bulach, CC BY-SA 4.0. At its peak in 1994, Argyle produced 42 million carats of rough diamonds in a single year. By 2018, annual output had fallen to 14 million carats — still enough to make it the largest diamond producer in the world by volume. Over its full operational life, the mine yielded more t...

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Image: W. Bulach | CC BY-SA 4.0

Argyle Diamond Mine: Closure and What Comes After

Sun, 29 Mar 2026 15:05:37 GMT

Photo credit Brian W. Schaller, FAL. Rio Tinto announced in 2018 that Argyle was no longer economically viable. On 3 November 2020, production stopped. The remaining ore was processed over the following six months; diamond sales continued into 2022 in both Australia and the United States. The site is now being decom...

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Image: Brian W. Schaller | FAL