This 18 kg calcite, 45 x 30 x 30 cm, comprised the back wall of a 2 meter pocket Wes Gannaway and I (John Cornish) collected several years ago. The most extraordinary feature of this specimen, other than its monstrous size, is the 2.5 cm wide channel, 7.5 cm long, which underlies one of the main crystals. Within it freely travels a 2.5 cm bubble!
Several other calcites from this find also contained multi-phase inclusions, though this was the largest and most dramatic.
Coming from the dark cool confines of the pocket, I've always been amazed that this specimen never exploded, especially as we were collecting during the height of Summer in the blazing sun. Thankfully the care we showed in immediately wrapping the specimen and storing it in the shade paid off. This is the largest fine calcite group I've ever seen from the state of Oregon.