Thomas Sabo Hallmarked 925 Sterling Silver Charm Club July birth stone, synthetic ruby charm/pendant. Long before the modern twelve-month calendar was developed, astrologers associated the religious symbolism of stones with the twelve signs of the zodiac. The gemstones allocated to each sign of the zodiac have changed over the centuries. THOMAS SABO uses the current colour allocation for its birth stones. Including a lobster clasp which can be combined with a cord, chain or necklace. Size;0.9cm