The natural fancy colour diamonds belong to a “large alluvial diamond deposit” and display the “highly attractive” fluorescence under ultraviolet light.
Patrick Stringer, director IBDH, said, “The purple colour came as a complete surprise and may indicate that a new primary source of diamonds is nearby.
"So far, we know that these special diamonds are contained within a specific area known as the L-Channel. We have a very detailed understanding of the L-Channel deposit, but we never expected to discover that brilliant fancy yellow diamonds would fluoresce purple.”
Fluorescence is caused by variations in the atomic structure. According to the Gemological Institute of America (GIA), approximately 25–35 per cent of diamonds show fluorescence, with the most common colour being blue. Diamonds can also display yellow, orange, red, white, and green fluorescence – however, this is considered rare.
While fluorescence is not a grading factor, unlike colour, clarity, cut, and carat, it is included in GIA grading reports.
Some consider fluorescence undesirable, believing it creates a “milky”, “hazy” or “oily” appearance in white diamonds. However, Russian mining conglomerate Alrosa – the world’s largest diamond producer by volume – recently began marketing naturally fluorescent stones under its Luminous Diamonds brand.
IBDH has tasked Delta Diamond Laboratory in Perth with further investigating the nature of the Ellendale diamonds' unusual fluorescence.
John Chapman, a scientist with Delta Diamond Laboratory, said, “Violet or purple fluorescence is normally associated with blue diamonds, so the fluorescence of these Ellendale fancy yellow diamonds is quite rare.”
The Ellendale diamond field is estimated to contain at least 1.3 million carats of gem-quality diamonds, including fancy yellow diamonds. IBDH is one of two companies currently exploring diamond deposits in the region, which is located approximately 135km east of Derby in the West Kimberley.
ASX-listed Gibb River Diamonds – formerly known as POZ Minerals – was granted exclusive mining and exploration leases for another section of the site in January 2020; the main Ellendale Mine had lain dormant for five years following the liquidation of its previous operator, Kimberley Diamond Company.
Ellendale – which has been producing diamonds since 1976 – was once the world’s premier source for yellow diamonds. With the closure of the Rio Tinto-operated Argyle Mine at the end of 2020, it remains the most promising option for Australian commercial diamond production.
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