Royal blue

"Royal blue" is the trade color call for a deeper, more vivid blue sapphire with a slight violet modifier — the color associated with the finest Mogok (Burma) sapphires and certain top-grade Mozambique and Madagascar material. SSEF and Gübelin use "royal blue" as a color description on origin reports when the saturation, tone, and hue meet their internal reference standards; GRS uses "Royal Blue (GRS-type)" with explicit defined criteria.

The defining feature is saturation paired with depth of tone. Cornflower blue (associated with Kashmir) is medium in saturation and medium in tone, with a velvety character; royal blue is high in saturation, medium-dark in tone, and crisp rather than velvety. The slight violet modifier distinguishes royal blue from the pure-blue tone that some Ceylon material shows; the violet is the signature that defines the top-of-market saturation for blue sapphire.

Royal blue is historically associated with Mogok material from Myanmar. Top-grade Mogok blues run royal blue almost by default — the geology produces low-iron, vivid-saturation crystal that, when cut to maximum color, reads as royal blue. The challenge with Mogok is supply: production has been intermittent for decades, and the available 3-ct-plus unheated royal blue Mogok stones at the top of the market are rare.

Mozambique royal blue sapphires entered the market in significant volume from the late 2010s onward. The Mozambique material from the Niassa Province deposits can reach royal-blue color at the top of production; the chemistry is distinguishable from Mogok via LA-ICP-MS, so origin reports separate the two sources cleanly. Madagascar (Andranondambo, Ilakaka) also produces royal blue material; the finest Madagascar stones rival Mogok at the top of color, though the trade premium for Mogok origin remains substantial.

The trade premium for the royal-blue color call is meaningful but smaller than the premium for the corresponding cornflower-blue Kashmir call. A 3 ct unheated royal-blue Mogok with Gübelin or SSEF paper trades $10,000 to $40,000 per carat; a 3 ct unheated royal-blue Mozambique with comparable paper trades $4,000 to $12,000 per carat. The same stones without the royal-blue call but at similar visual quality trade at 20% to 40% discount.

The color call requires SSEF, Gübelin, or GRS paper to be trade-recognised. "Royal blue" used in retail marketing without a corresponding lab report is sales language. A buyer offered a royal-blue sapphire should require a copy of the report and verify the color call appears in the supplementary remarks; the visible color alone is not the credential.