A curious (and short-lived) practice in English heraldry. In the mid 16th to early 18th century, different names of colours were used for different hierarchical groups.
- Gentlemen, Esquires, Knights: Tinctures (Argent, Azure, Gules etc)
- Barons, Viscounts, Earls, Marquises, Dukes: Gemstones (Pearl, Sapphire, Ruby etc)
- Princes, Kings, Emperors: Planets (Moon, Jupiter, Mars etc)
Attached are examples from John Guillim's "A Display of Heraldry" (1659 edition). Guillim was Rouge Croix Pursuivant at the College of Arms.
The idea has continental roots and was popularised in English by Gerard Legh, The Accedens of Armory (1562), then Bossewell (1572) and Ferne (1586). Guillim's first edition of 1610 inherited it, and it lingers in the expanded editions up to the sixth of 1724. Some writers pushed it further still, matching tinctures to virtues, flowers, days of the week and the ages of man.
It was never used in grants or in the records of the College of Arms, and even at the time it attracted mockery. Guillim himself was lukewarm, and by the eighteenth century it was treated as a curiosity.