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Let's Rock => Rock Talk => Topic started by: dunninald on September 23, 2018, 03:35:02 AM

Title: Questions abour agates, kidney stones and geological histories
Post by: dunninald on September 23, 2018, 03:35:02 AM
I've always wondered how agates formed; some mysterious alchemy of heat, pressure and minerals.  A recent story led me to https://news.illinois.edu/view/6367/693531 where intrepid researchers are cabbing their kidney stones, for to do science stuff.
Summary on https://www.thedailybeast.com/the-bizarre-beauty-inside-your-kidney-stones-3/2 (image attached).

So science finds that kidney stones partially dissolve and regrow again and again as they form, creating micro-crystalline rings.

What is the latest on how agates form? Should we add "partially dissolve and regrow again and again" to the familiar story of gradual crystallisation? What about the measurement techniques the Illinois scientists used? Have they been used by geologists on chalcedony, and what did they reveal?