38.5 Carat Black Opal From Ridge, Australia. Created in 1990 by North Star Jewelers of Portland, Oregon. The gem displays a slightly marbled back of medium gray to black potch. The face has been contoured cut with an excellent degree of polish. This large and impressive gem shows a medium intense play of color that is primary blue with nice medium dark under-tones of green. Some oxide webbing is visible in the face. There is a chip at the top tip. The shape is free form and is approximately 3 to 5.0 mm thick. 31 to 38 mm across.