This is a symbol for Gemini pendant or charm in sterling silver 925. This is an air symbol and the birthdays are May 20th through June 20th. It is said the ruling planet is Mercury. The sign represents the twins and it is also known as glyph. This pendant measures 22 mm tall including the bail, 15 mm tall not including the bail and 15 mm wide. This piece is marked with 925 for the silver purity and a marker's mark that I cannot out. Weighs 2.21 grams total weight.