The premium for unheated sapphire over comparable heated stones has widened through 2025. In commercial sizes, 30% is common. In fine one to three carat royal blues with top lab reports, premiums of 100% or more appear regularly in wholesale quotes.
Guild and trade data suggest the proportion of stones testing unheated continues to fall year over year. When supply shrinks, buyers who insist on no-heat papers pay disproportionately.
Heat treatment is not a fraud in the trade; it is standard for most commercial corundum. The issue is disclosure. A heated stone sold as unheated destroys trust. Laboratories stating no indications of heating became the gatekeeper for the premium.
Face-up colour still matters more than treatment label for jewellery use. A vivid heated oval can beat a dull unheated stone at the same price. Investment and collector buyers are the segment driving premium expansion.
