Approximately 6 to 8 million years ago (Miocene epoch), volcanic activity occurred in western Utah and deposited an extrusive igneous rock called rhyolite. Trapped gasses formed cavities within the rhyolite, and millions of years of ground-water circulation allowed minerals to precipitate into the cavities. The result is geodes with spherical shapes and crystal-lined cavities. Roughly 32,000 to 14,000 thousand years ago, a large body of water known as Lake Bonneville covered most of western Utah. The lake’s wave activity eroded the geode-bearing rhyolite and redeposited the geodes several miles away in the Dugway geode bed area as lake sediments. Most geodes are typically hollow whereas others are completely filled with massive, banded quartz. The most common mineral found within the geodes is quartz in various colors: clear (rock crystal), purple (amethyst), and pink (rose).
A more general term for all varieties of quartz that are made of microscopic or submicroscopic crystals, the so-called microcrystalline varieties of quartz. Examples are the different types of agate, jasper, and onyx.
In the strict sense, and in scientific literature, "chalcedony" designates aggregates of parallel grown ("fibrous") quartz crystals of microscopic and sub-microscopic size.
Possible Healing qualities ...
Blue Chalcedony is believed to be a helpful stone in creativity, aiding in increased mental flexibility as well as verbal adeptness, stimulating capabilities in learning new languages and improving memory. It is also used to improve confidence and. Blue Chalcedony is revered as an aid in regeneration of mucus membranes and strengthening the immune system. Blue Chalcedony is believed to have an anti-inflammatory effect, helping to lower body temperature, decrease blood pressure, and clear and heal the lungs.
Sources - Utah Geological Survey; The Quartz Page