Solid black crystal "core", These opals fill cavities or spaces in the clay layers.   Black Rootbeer crystal back lit Virgin Valley Opal.
A  1 3/4"x3/4"x1/2" black crystal core with the full play of Virgin Valley color.
Rootbeer core 360 degree color Virgin Valley Opal.
Looking back up the dome.
Bluish Green plates of color with a prismatic effect.
The colors shift around like rolling bars or tubes of prismatic rainbows. $675 for this jelly specimen.