The connoisseur’s stone, still undervalued
For centuries the finest spinels were mistaken for rubies. The Black Prince’s Ruby in the Imperial State Crown is a spinel, as is the Timur Ruby. That historical confusion suppressed the stone’s reputation long after gemmology could separate them, and the market has only recently caught up.
Spinel’s structural advantage is that it is effectively never treated. What you see came out of the ground that way, which means no premium is required to secure untreated material: it is the norm rather than the exception. The Mahenge deposit in Tanzania, discovered in 2007, produced a vivid pinkish red that briefly electrified the trade, and cobalt-bearing material from Luc Yen in Vietnam remains among the rarest coloured stones in commerce.
Cobalt-bearing blue spinel from Luc Yen in Vietnam is the exception to spinel’s value discount, trading well into five figures per carat. Untreated spinel of fine colour is still priced well below ruby of comparable quality, which makes it the most accessible of the fine stones.