I have 18k Yellow gold o chains. The diamond cut make it shine in the light. Perfect for any ocasión, use it with your favourite pendants. SORRY THE PRICE IS FIRM, PLEASE DON’T OFFER It is stamp AU750 (Au is the symbol for gold on the periodic table, and 750 means the jewelry is 18 karat gold) Specially in fine jewelry as Tiffany, you can find the mark Au750 rather than 18k. Metal: Real gold Purity: 18k Yellow Adjustable length: 16 to 18 inch Thickness: 1.1mm Buy with confidence NOT PLATED OR FILLED OR VERMEIL