Gemini (22 May-21 June) is the third sign of the zodiac, its element is Air.A rare, vintage reverse crystal zodiac charm sits with three other charms to celebrate the star sign Gemini: a Gemini twins symbol, a pale lilac sparkling Swarovski crystal to represent an alexandrite birthstone and a Mercury Meniscus charm, the ruling planet of Gemini. All hang from a fine sterling silver chain in a choice of four lengths (please select preferred length below). Metal: All sterling silver.