Rockhounding in Arizona

Arizona is well known for its petrified wood because of the Petrified Forest National Park, and petrified wood ranks third in value of commercially produced gemstones. It is generally accepted that the Park contains the most colorful examples of silicified logs in the world.

Petrified wood occurs in every county in the State, but the commercial production is essentially from privately owned lands in Navajo and Apache Counties near the Petrified Forest. Federal regulations restrict collecting petrified wood on public lands to 250 pounds plus one piece per person per year, none of which is supposed to be sold commercially. The regulation essentially eliminates production from federal lands. Pieces as small as 1/4-inch to sections of logs 5 feet in diameter are recovered from the surface of the ground or with minimum excavations for use in the lapidary trade.

Arizona petrified wood has the broadest range of applications of any gem material produced in the State. The material is suitable for tumble polishing for use in baroque jewelry or for cutting into cabochons for jewelry and display. Freeform and calibrated slabs are polished for pen and pencil set bases and bases of other items, and polished slabs are used for clock faces. Additionally, large blocks, limb sections, and geometric shapes are used as bookends and decorator pieces. Objects of art, principally carvings, are produced, and furniture such as coffee and end tables are made from the petrified wood.

Arizona is the only State currently to have commercial production of fire agate. Fire agate is a form of chalcedony which contains inclusion of iron oxides that result in a play of colors much like that of precious opal. Eleven operations in Arizona report either commercial production of fire agate or dig-for-fee production. The material is produced in Graham, Greenlee, Maricopa, Mohave, and Yuma Counties.

Fire agate is cut into freeform and calibrated cabochons for use in the manufacture of silver and gold jewelry. The material is popular in the southwest and with hobbyist lapidaries throughout the United States. Fire agate also has been used and is currently used in Indian style jewelry.