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How to Find the Fire in Fire Agate

Fire agate is a quartz-based rock with layers of iron oxide in chalcedony, which results in iridescence. It occurs in nodules of milky or grayish translucent chalcedony. Sometimes it is found in botryoidal growths in geodes and in chalcedony roses. Fire agate appears as a dull, reddish brown layer, but when the surface layers are removed, the rainbow colors of iridescence are exposed. The fire is brought out by tumbling, trimming and grinding off the outer layers to expose the iridescence. Polishing magnifies the fire.

  1. Remove the matrix, then tumble polish it.
  2. When polished, remove excess stone around the edges—then polish and set.
  3. Allow the stone to retain its irregular shape and polish slowly so you don't go through the fire layers. The graceful natural shapes are superior to those cut to calibrated sizes, as the best fire does not always fit a mold.
  4. To set it off, mount it in a custom made gold or silver setting.

Via Magic Valley Gems 12/01, Chips 8/01, Gem Time 11/01