Natural Fancy Violet Diamond
Natural Fancy Violet Diamond
The rarest fancy colour after pure red, almost exclusively from Argyle
A natural fancy violet diamond is a diamond whose body colour reads as violet — a hue with a measurable blue component that distinguishes it from purple in the GIA fancy-colour grading framework. Natural fancy violet is among the rarest of all fancy-colour categories. Fewer than two dozen significant natural violet diamonds are documented in the public literature, and almost the entire documented production has come from a single source, the Argyle mine in Western Australia, which closed in 2020. The cause of colour is not definitively established but appears to involve hydrogen-related defects in plastically deformed diamond, in proportions distinct from those that produce purple.
Cause of colour
The detailed defect chemistry of violet colour in natural diamond is less well characterised than for the more common fancy colours. Spectroscopic studies of Argyle violet diamonds, published principally by GIA and by Rio Tinto's research collaborators, indicate hydrogen-related absorption features and signatures consistent with significant plastic deformation. The shift in hue from purple toward violet — that is, toward a bluer position in colour space — appears to correlate with greater hydrogen content in some studies, although the data are limited by the small population of stones available for study.
The geological setting that produces violet colour appears to be the same broad cluster of conditions that produces the Argyle pinks, purples, and reds — diamonds that experienced significant plastic deformation in transit from the mantle, with hydrogen incorporation at concentrations and configurations that produce the violet shift in a small subpopulation. Why Argyle so dominates the production of violet diamonds while other major mines yield essentially none is not fully understood; the most plausible explanation is the unusual combination of pressure, temperature, and impurity profile in the Argyle source environment.
Argyle and the Tender
The Argyle Pink Diamonds Tender, an annual auction of the mine's most exceptional stones held from 1985 to 2021, included occasional violet lots as the rarest single-stone offerings. The 2.83-carat Argyle Violet — the largest violet diamond ever recovered from the mine — was the centerpiece of the 2016 Tender and sold for an undisclosed sum estimated by trade press at well above $4 million per carat. Other documented Argyle violets weigh under 2 carats, with the typical violet from the mine in the 0.10 to 0.50 carat range and the Tender stones at the upper end of that scale.
The closure of Argyle in November 2020 ended new violet supply from the dominant historical source. Stones from the final Tenders and from secondary-market inventory continue to circulate in private and auction markets, but no new supply is in prospect at meaningful volume.
Distinction from purple, blue, and grey
The hue boundaries that separate violet from purple, blue, and grey are determined by colour position in standard reference space and are evaluated by GIA and other major laboratories under controlled grading conditions. Violet-blue and grey-violet stones are recorded as such on grading reports; pure violet without modifier is the rarest grade. Some Argyle violet stones have been graded with grey or blue modifiers, while the most exceptional stones have received pure-violet grades.
The boundary between violet and Type IIb blue (boron-coloured) diamond is particularly worth noting: blue diamonds with strong violet modifier and violet diamonds with strong blue modifier sit close to one another in colour space but have entirely different defect chemistry. Boron-coloured Type IIb stones are semiconducting and have characteristic infrared absorption at 2802 wavenumbers; violet stones with hydrogen-related colour are insulating and lack the boron signature. Laboratory testing makes the distinction routinely.
Grading and pricing
GIA grades natural fancy violet diamonds on the fancy-colour scale and notes the modifier explicitly. Most Argyle violets receive grades in the Fancy Vivid Violet, Fancy Violet, or modifier-noted ranges. Per-carat prices for stones above one carat exceed $1,000,000 per carat for the most exceptional examples; the 2.83-carat Argyle Violet's price-per-carat was reported in trade press as setting a record for any violet diamond. Smaller stones (under 0.50 carat) trade at lower per-carat prices but at substantial premiums to comparable pinks and purples.
The market for natural fancy violet diamonds is small, specialist, and dominated by collector demand. Public auction sales are rare; most transactions occur through private placement among the small group of dealers and collectors who specialise in Argyle Tender material.
Authentication
Three documentation requirements are standard for a natural fancy violet diamond: a GIA, AGS, or HRD grading report confirming natural origin and the colour grade; the original Argyle Tender certificate where applicable, which adds substantial provenance value; and detailed chain-of-custody documentation through the dealer or auction house. The Argyle certificates were issued for Tender stones and contain laser-inscribed identification numbers on the stones themselves; matching the stone to the certificate is part of standard authentication.