Saturation 5 — Strong on the GIA Scale
Saturation 5 — Strong on the GIA Scale
Fine-quality colour with high chroma and no visible neutral component
Saturation 5 is the second-highest grade on GIA's six-point saturation scale, denoting strong colour with high chroma and no visible grey or brown component. Stones graded saturation 5 are considered fine-quality material across the major coloured-stone species and command significant premiums over the lower grades. In sapphire and ruby in particular, saturation 5 is often the practical ceiling for natural unheated stones, with saturation 6 (vivid) reserved for exceptional examples that combine high chroma with the precise hue and tone that earn the top trade designations.
In the trade
Saturation 5 in sapphire produces the strong, clean blue typical of the better Burmese, Madagascan, and Sri Lankan stones; in ruby, the rich red associated with fine Burmese and Mozambican material; in emerald, the deep saturated green of better Colombian and Zambian stones. At this grade the colour is unmistakably the dominant feature of the stone, and the price premium over saturation 4 is large — frequently several multiples for the same hue and tone in a comparable cut.
The unheated question
Saturation 5 in unheated corundum is materially rarer than the same grade in heated material, since heat treatment is principally used to push saturation upward by reducing residual blue or yellow component in the trapped iron and titanium chemistry. An unheated saturation-5 stone with a fine hue is among the more sought-after categories in the contemporary coloured-stone market, particularly in Burmese ruby and Kashmir or Burmese sapphire. Laboratory documentation from a recognised laboratory — Gübelin, SSEF, AGL, GIA, Lotus — is the trade convention for unheated claims at this quality. See also saturation, saturation 1, saturation 2, saturation 3, saturation 4, saturation 6.