The agate came to Bowers in November via Brazilian gemologist Lucas Fassari, who had acquired it in a batch of many agates from Soledade.
Bowers immediately purchased the Cookie Monster agate, but didn’t post it online until Jan. 16, as he was ill with COVID-19.
Agates are a form of quartz, the crystalline form of silicon dioxide, that develop within cavities in volcanic rocks. The cavities are formed by gas bubbles in hot lava.
(Kennedy News & Media)
Over time, as the lava cools, water infused with silicon dioxide percolates through the cavities. As the water evaporates, the silicon dioxide is left behind on the cavity walls, creating colorful layers of crystals. The colors are caused by chemical impurities in the silicon dioxide and by the spacing of the crystals.
Some agates completely fill their volcanic voids, but many leave small spaces inside, lined with sparkly, inward-facing quartz crystals. In the case of the Cookie Monster agate, these voids just happen to look like a pair of Muppet eyes and an enthusiastically grinning mouth.
“It is somewhat uncommon to find a face shape in agates, but in many instances it’s like looking at the clouds. You kind of see a face,” Bowers said.
“What makes the Cookie Monster unique is there is just no doubt: Clear-cut, it is Cookie Monster, no explanation required.”
Another unique feature of the Cookie Monster agate is that the face appears on both sides of the cut stone, Bowers added. Usually the voids are not lined up so neatly as to create a mirror image.
For now, Bowers said, he plans to keep the stone. It may eventually end up in a museum or in the hands of a high-end collector, he said.