Symbolism
Mystical correspondences of heraldic tinctures

Friar (pp 343-4) notes, “In 1583, Richard Robinson … produced a book of fifty-eight blazons in verse, each relating to a member of King Arthur’s court. Based on La Devise des Armes des Chevaliers de la Table Ronde, published in Paris in about 1546, it contains a series of ‘significations’ of the tinctures…”

Woodcock & Robinson (p. 53) cite Joseph Edmondson who, in his Complete Body of Heraldry (1780), dismisses the practice thus: “White, say they, denotes chastity; black constancy; blue loyalty, &c, &c. But as to such ridiculous fancies, the mere mention of them is fully sufficient.”

Pace Edmondson’s caveat, the following table is based on Friar’s list, with some additions (in square brackets). The symbols shown in the fourth column are the astronomical symbols of the planets and the alchemical symbols of the metals.

^* Element and temperament (humour) are mismatched; compare gules and azure, and see here.
^† Inferred from Saturday, but assuming that ruddy copper is correct, the planet should really be Venus, (and the weekday Friday).
^‡ The planet should be Saturn, (and the weekday Saturday) and the metal lead.

During the fifteenth and sixteenth centuries it became fashionable to blazon the tinctures in the arms of kings with the names of the planets and of nobles the gemstones.

This practice does not survive, except in one instance where it is particularly apt: the 1967 grant of arms (right) to what is now the Gemmological Association and Gem Testing Laboratory of Great Britain  :

Pearl (argent) on a cross formy quadrate throughout quarterly ruby (gules) and sapphire (azure) a closed book bound and clasped topaz (or) the cover set with an emerald environed of pearls between two sapphires in pale and two rubies in fess between in chief within an annulet topaz (or) a rose-cut diamond proper in fess two lozenges pearl (argent) each charged with a fillet cross diamond (sable) and in based a ring topaz (or) gemmed pearl (argent)

Note that this balzon uses topaz, rather than carbuncle, for or, possibly to avoid confusion with the device that the lynx in the crest is holding: an escarbuncle, “heraldry’s special emblem of gemmology”.