spheircal
"too spherical" - that is exactly the indicator. To achieve a spherical form the deposition would have to have been made with some freedom from gravity - say in a uniformly accelerating plasma jet -
I suppose one could have gas bubbles, with deposition taking place inside empty bubbles, but there is no sign of deformation, as one sees in many geodes. Furhtere there is no crystal to maintain the speherical shape -
ep