THis is a really nice specimen of prehnite from O&G. I once attended a lecture on how these hollow spheres of prehnite formed. I believe they said some sort of colloidal gel was involved. At any rate, they are found from time to time at O&G, but this one is uncommonly large and well formed. The color is cream with a yellow tint. It sparkles from every side and was collected by my former digging partner, Joel Sweet. 6.2 x 5 x 3.5 cm. No damage. Very unusual!