The topaz represents “or” (gold), or the planet Sol. The pearl or crystal represents “argent” (silver), or the planet Luna. The ruby represents “gules” (red), or the planet Mars.
The sapphire represents “azure” (blue), or the planet Jupiter.
The diamond represents “sable” (black), or the planet Saturn. The emerald represents “vert” (green), or the planet Venus.
The amethyst represents “purpure” (purple), or the planet Mercury.
for the MONTHS. Each month is supposed to be under the influence of some precious stone—
January: Garnet. Constancy.
February: Amethyst. Sincerity.
March: Bloodstone. Courage.
April: Diamond. Innocence.
May: Emerald. Success in love.
June: Agate. Health and long life.
July: Cornelian. Content.
August: Sardonyx. Conjugal fidelity.
September: Chrysolite. Antidote to madness.
October: Opal. Hope.
November: Topaz. Fidelity.
December: Turquoise. Prosperity.
for SIGNS of the ZODIAC—
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894