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How to Polish Chalcedony

Chalcedony is a form of quartz crystal that can be found in many different colors when it is interspersed with other minerals through sedimentary processes. Agate is technically a form of chalcedony, as are moss agate, onyx, carnelian and jasper. Like quartz, chalcedony is extremely hard, and can be cut and polished to a high sheen to better display its amazing array of colors and patterns.

Things You'll Need

Rock tumbler
Cold water
Coarse abrasive tumbling grit
Medium abrasive tumbling grit
Prepolish tumbling grit
Polish (cerium oxide)

Instructions

- 1
  Place your pieces of chalcedony in the rock tumbler barrel, and fill with cold water until the rocks are just about covered. Put in 1 tsp. of coarse grit per 1 lb. of chalcedony. Try to fill the barrel with pieces of various sizes, and fill it 3/4 full for the best possible grind.
- 2
  Tumble for five days.
- 3
  Remove the chalcedony and the water from the barrel, then rinse the rocks extremely thoroughly to remove all traces of the old grit.
- 4
  Cover the rocks with cold water and add 1 tsp. medium grit per 1 lb. of rock.
- 5
  Tumble for eight days.
- 6
  Remove the rocks and water again, and again rinse extremely thoroughly.
- 7
  Cover the rocks with cold water, adding 1 tsp. prepolish grit to the barrel per 1 lb. of rock, and tumble for another eight days.
- 8
  Remove the chalcedony from the barrel and rinse with soap and water. This is the most important wash; they need to be as sparkling as possible before you polish them.
- 9
  Cover the rocks with water again, and put in 3/4 tsp. of polish per 1 lb. of rock.
- 10
  Remove the stones every two days to check on the polishing process, and repeat step 9 if they're not as shiny as you want.

Rock Collecting