This delicate heart pendant is made of genuine blue Opal. The chain is fine solid sterling silver chain. Size of necklace is 16 1/2 inch (42 cm). On request you can have this with a 18 inch or 20 inch at no extra cost; just let me know. Available in Pink Opal, White Opal and Green Opal as well (please mention requested color at the checkout) .Thank you.