Historically, Spinels were frequently misidentified as rubies, one of the best known examples of this can be seen in the Crown Jewels where the ‘Black Prince’s Ruby’ is actually a Spinel. It weighs about 170 carats and is set above the Cullinan II diamond in the Imperial State Crown. It is one of the oldest of the Crown Jewels, having been acquired in 1367, by the Prince of Wales – Edward of Woodstock (who came to be known as The Black Prince) as payment for a battle victory abroad.
Spinels are known to exhibit an array of unusual optical effects, including ‘asterism’ – whereby three intersecting bands of light reflection form a star shaped pattern on the stone, ‘chatoyancy’ or ‘cat’s-eye’ which is one single band of light reflection bisecting the stone, (both of these require the stone to be cut as a cabochon in order to see the effect) as well as a ‘colour change’ effect where some stones will appear different colours or shades of the same colour when viewed in differing light conditions.
Amongst the most important current commercial sources are Burma, Tanzania and Vietnam and some of the rarer colours are extremely rare and expensive.
Description: Spinel occurs in a range of colours, from various shades of blue through purples and pinks to hot vivid reds, they can be found in Tanzania and Burma amongst other places.
Hardness: 8 on Mohs Scale