These are distinctly different from most of the other Cubuk thundereggs in that they form seams and fissures rather than neat cores. They are often fragmented and generally random in shape, but they also have some of the most beautiful agate of any of the Cubuks.
Large Cubuk Thunderegg with red matrix and seams of Dark Agate.
Beautiful Cubuk Russet Thunderegg with Soft Pink Agate