Chrysocolla 8-10mm Irregular Cube A Grade - 15-16 Inch Color_Green This variety of opal is

This variety of opal is named "dendritic" for the small inclusions within it that resemble moss or ferns

In lower grades it can be transparent to opaque and is commonly light blue

It's often found in large masses and can be colorless

so named because the ancient Incas believed the stone to be the petrified blood of their ancestral rulers

Display them together

Chrysocolla 8-10mm Irregular Cube A Grade - 15-16 Inch Color_Green This variety of opal isChrysocolla, a hydrous copper silicate, is often mistaken for turquoise due to its rich blues and blue to greens. It often also occurs with colors of rust, copper, black, white and reddish brown in speckles, veins and brecciated patterns. It is a very soft stone typically found near copper deposits. Chrysocolla was first described by Theosphrastus, a Greek philosopher and botanist who also named the stone, in 315 BCE.