Royal Blue
Royal Blue
The trade colour designation for medium-dark, vividly saturated blue sapphire
Royal Blue is a trade term for a rich, medium-dark blue sapphire with vivid saturation and a slight violetish secondary hue. The designation describes a colour intensity between cornflower (lighter, purer blue) and the darkest saturated blues, characterised by strong face-up colour without the windowing of overly light material or the extinction of overly dark material. Royal Blue is one of the most consequential colour grades in the coloured-stone trade, and the formal designation on a laboratory report can substantially affect a sapphire's market value.
The colour itself
The royal-blue range falls in the medium to medium-dark tone band of the GIA coloured-stone reference, with strongly to vividly saturated colour. In hue, the term applies to blues that range from a pure blue to a slightly violetish blue, but excludes greenish blues. The eye perceives royal-blue stones as deeply coloured but still bright, with the colour holding under most lighting conditions rather than going dark in incandescent or grey in fluorescent.
Stones that fall outside this band carry other trade designations: lighter, purer blues are described as cornflower; darker blues as deep blue or, at the extreme, inky; greenish blues as teal or simply blue without the royal designation.
Laboratory designation
Two laboratories issue formal Royal Blue designations on their coloured-stone reports: GRS (Gem Research Swisslab) and Lotus Gemology. Each laboratory has its own colour-reference standards and applies the term according to its proprietary criteria. GRS uses a specific tone-and-saturation cell of its colour reference; Lotus uses a master-stone reference and graded comparison. The two laboratories' Royal Blue designations are not identical but overlap heavily, and stones meeting one are often comparable to stones meeting the other.
Other major coloured-stone laboratories — Gübelin, SSEF, AGL, GIA — describe colour in narrative form on their reports but do not issue a Royal Blue designation as such. Buyers seeking a formal Royal Blue mark on the report typically commission GRS or Lotus, often in addition to a primary report from one of the other laboratories.
Origin associations
Royal-blue colour is most commonly associated with Burmese sapphires from the Mogok Stone Tract, where the combination of geology and trace-element chemistry produces stones in the royal-blue range with relatively high frequency. Sri Lankan sapphires from Ratnapura and Elahera also produce royal-blue colour, often after heat treatment from less saturated rough. Madagascar's Ilakaka deposit is the third major source. Each origin produces stones with subtle differences in hue and behaviour, but the trade designation is colour-based rather than origin-based — a Royal Blue Madagascar sapphire and a Royal Blue Burma sapphire are both Royal Blue, though they trade at substantially different prices.
In the trade
A Royal Blue designation on the report typically adds a measurable premium to a sapphire's market value, with the size of the premium dependent on origin, treatment status, and the underlying quality of the stone. For Burmese unheated material, the Royal Blue designation can lift prices substantially over comparable stones without the formal grade. For heated material from less prestigious origins, the premium is smaller but still real. The designation is most influential at the upper end of the market, where comparison and benchmarking are most rigorous.