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The Gemstone Fire Agate


Fire Agate Cabochon
REFRACTIVE INDEX: 1.544 - 1.553

What is Fire Agate?
Fire Agate is not a well known gem.
It has colors that are brighter and
sometimes more beautiful than opal.
Without the risk of cracking, fading
or easily scratching.

Agate is probably one of the most common and well known gemstones. This variety of silica is generaly formed by volcanic activity. Fire Agate is thought to be formed when hot water saturated with colloidal silica and iron oxide. Invades cavities in regular rock below the earth's surface.

When it begins to cool. Chalcedony with iron oxide begins to grow on any available surface. The solution grows layers of silica and iron oxide. Many shapes and colors are formed by the mineral impurities in the silica.

The alternating silica and iron oxide layers are called Schiller. The Schiller layers are small enough that light passing through them. Forming an interference of colors known as Fire.
These impurities give fire agate the distinction of "Gem", rather than just agate.

As the iron oxide in the solution runs out, colorless chalcedony continues to grow. Producing the typical brown and white rough fire agate. The iron oxide is what gives this gem it's basic brown color.

Some of the most colorful and brilliant fire agates are from Arizona. The micro-thin layers in this material, diffract light, back to the eye in rainbow patterns. Creating brilliant bubbles and sheets of red, green, yellow, and the elusive blue. It is truly remarkable material. From famous mines such as, Deer Creek, Slaughter Mountain and others.

Cutting Fire Agate:
You must essentially reverses nature's process by grinding and polishing away layers, following natural contours, until only the fire is visible.

It's best to work this agate with a diamond wheel to expose the fire layer. Then switch to a Dremel or a Foredom tool. With a good sintered diamond bit.

Now patiently work away the remaining material. Following the natural contours as best as possible. Until you are right on top of the fire layer. As you might imagine, one layer too far and the stone is ruined. Tumble them with your remaining junk fire agate or other agate material

Public Fire Agate Diggs:

Opal Hill:
Is actively producing fire agate and rock hounds still frequent the mine for it's gem-quality stones. The mine is privately owned, but open to the public for a small collecting fee, which is well worth it. With some hard work and effort, almost everyone leaves Opal Hill satisfied with the fiery agate they take with them.

From Interstate 10, take Wiley Well Exit and head south on the graded dirt road for 17 miles. You will see a sign for Opal Hill Mine on the left side of the road. Go left here and travel east for a few miles on a rough dirt road. A high clearance vehicle is needed to navigate on the last dirt road to the mine.

Opal Hill can also be accessed by way of Palo Verde. Take Highway 78 south from Interstate 10 until you reach 4th street exit in Palo Verde, go right. Follow the Opal Hill signs for 9 miles until you arrive at the mine.

The cities of Indio and Blythe offer complete accommodations.
Blythe is the closest to the area.

The Opal Hill Mine is located on BLM land, which is an open area for camping. Opal Hill Mine has a couple small trailers which they offer to patrons at no additional charge.

Coon Hollow Campground and Wiley Well Campground are BLM facilities.
Equipment & Tools:

Make sure you pack plenty of food and water since the mine is located on BLM land with no stores nearby. Bring big buckets to haul your precious rocks home and a chisel, wire brush, pick, shovel, sledge hammer and any other tools you need

For information on the mine and tours available contact: Craig at 760-424-6504 or by email at More Info:

Black Hills Rockhound Area:
makes a great half-day adventure for rock collectors. This undeveloped area is open for agate digging by the public without fees or permits. Although no facilities are available, primitive camping is allowed for up to 2 weeks. Shovels and picks can be used to dig for fire agate. Most agate is found within the first 2 feet of the surface. Agates can be discovered on the surface near the washes. Please backfill holes.

20 miles east of Safford. Access: Drive east of Safford for 10 miles along US Highway 70, then take US Highway 191 north to a point just beyond milepost 141. You will see the entry sign on the left. Follow the dirt entry road for 2 miles to the sign at the center of the rockhound area.

Road Conditions:
The entry road is best suited for high-clearance vehicles since it receives infrequent maintenance. Rain can cause washouts, but the area is generally accessible year-round to most vehicles.

4,100'-4,400' Facilities: Primitive camping pullouts. Attractions: Rock hounding, primitive camping.

Fall, winter, and spring have the most pleasant outside temperatures. Summers are extremely hot.

Shade and water are unavailable. Avoid mining claim posts.
For Further Information Contact:
BLM Website