Fieldtrip Report:
Crater of Diamonds State Park,
Murfreesboro, Arkansas,
April 2005,
by Phil Napier
Just thought I would send in a little report on our trip last weekend. We just purchased a travel trailer, and thought we would take it on a short shakedown cruise to the Crater of Diamonds State Park in Murfreesboro Arkansas.
We left Blue Springs on Thursday after work and drove to Fayetteville AR. And spent the night in the Wal-Mart Parking lot. It rained ALL NIGHT (With my bad back, I was sure glad I didn’t have to pitch a tent).
Friday morning early we drove on down to the Crater and set up camp, then off to the mine. This is the entrance to the mine from the visitors center:
The mine is advertised as the only Diamond Mine in the world where you can pay a small fee ($6.00/day) and keep what you find, to include Diamonds, Jasper, Agate, Quartz (and Amethyst), Calcite, Barite, Mica, and Lamproite. Several locals earn a decent living searching for and selling their diamonds. Most of the ones found are industrial quality, but a few very nice ones are found.
Some of the equipment that was used around the 30's to extract the diamonds from the Lamproite.
A tumber screen that was used to breakup the soil to seperate the rock from the fines.
A grinding wheel that has cultivator like devices to break up large rock.
This was the old Mining Building (Not much inside-Just some wood built in tables for sorting I assume)
GEOLOGIC HISTORY
The area is in the Ouachita Mountains (Similar to the Missouri Ozarks). They are not as impressive as the Smokies, but still nice.
Around 100 million years ago, the area was a coastline for the inland sea. Suddenly, it exploded creating a crater about 80 acres in size. After the initial eruption, small pyroclastic cones developed and spewed out ash and lampilli. This ash mixed with sediments from the adjacent Trinity Formation, then magma erupted (bringing with it the diamonds) from deep within the earth and formed the Lamproite Breccia Tuff ( it was originally called Kimberlite, but analysis determined that it was somewhat different than the African Kimberlites (due to some of the variations in the mineral makeup of the material). This lamproite is the diamond bearing material. The magma moved up slowly enough that the diamonds that were impregnated in the magma, were resorbed. Only the resulting Breccia tuff, contains diamonds. But there is about 80 million cubic yards, so the diamonds won't all be found for several centuries.
The Lamproite Breccia Tuff (Diamond Bearing Material).
Most of the Diamonds are found in the weathered material just above the intact breccia. This material is represented as a gravelly layer about a foot thick. Depth to this layer ranges from about 3 feet to over 15 feet. Most of the Tuff is this green color.Several notable diamonds have been found here including one that is flawless and perfect color. It started out as a 3 plus carat rough, and was slightly over a carat after it was cut. The State purchased the cut diamond from the finder for $36,000.00, a few years ago, and it is on permanent display there. Also the 4.5 Carat Canary diamond that Hilary Clinton wore during the inaugural was found here. It is named the Kahn Canary (after it’s owner).
This is a picture of the famous Star of Arkansas Diamond that weighted 27.21 carats.
The site for the mine is: http://www.craterofdiamondsstatepark.com/
The state plows the 37 acre pipe monthly to turn over the soil and expose fresh material. The plow leaves a furrow about 3 feet deep.
We worked hard Friday and Saturday digging, screening and concentrating material to bring home. I haven’t found any diamonds yet, but there’s always a chance. I have found some nice Quartz, Jasper, and a few nice small garnets.
This is a great trip for families. There were lots of Families there with their kids.
Camping is available right next to the mine. There are about 60 campsites ranging from tent to full hookup for RV's. There is also a couple of other private campgrounds and a few Motels.
Monday morning we drove up to Mount Ida Arkansas to the Wegner Phantom Crystal Mine.Well, that was our exciting weekend.
