13x11mm oval shaped Mexican fire opal set on sterling silver wire, with sterling bail and 18" sterling silver chain. dimensions: .95 x .45 inches. This opal is from Mexico. It has been left in the matrix (the rock that surrounds the opal) which helps protect the opal and also gives it a unique look. This opal is clear, a deep orange color, and has play of color in yellow, orange,red, and green.