Australian Dark Opal from Lightning Ridge

Gemstone Type: Natural Australian Dark Opal.
Origin: Lightning Ridge, NSW, Australia
Cut: Free-form Cabochon.
Colour: As shown; Mainly greens, blues, and yellows
Weight: 1.50 Carats
Dimensions: Approx 11mm x 8mm x 3mm
Body Tone: 7N (Those gemstones with a body tone of N5 to N9 are classified as semi-black-opal, rather than the nomaclure of black-opal.)
Brightness: B1
Treatments: None (No Enhancement)
Product Description:
(B1 grading) A worthy chaff pattern gemstone showing good fire. Classified as B1 on the Opal brightness chart (which goes from the brightest B1, to B7). Those stones with a body tone of N5 to N9 are given the nomaclure of semi-black.