Australian Blue Opal in Yellow Gold Sandman - 14ga Threaded endThis is a fantastic piece the Australian opal is bold and dynamic, with primary tones of blue and green at various angles and warm colors peeking through. Between the contrast of opal and gold and the colors in the opal itself, this one has tons of personality. 14ga threaded fit. Important Stuff: Style: 14ga Threaded end Material(s): 14kt Yellow Gold, Australian Blue Opal Color(s): Gold, Yellow, Blue, Green, Red, Orange Diameter: 5. 7mm (. 22")