ADVENTURES WITH ROCKS (TM): Badlands, Buttes, and Banded Agates- Collecting Agates in South Dakota

South Dakota is known for its amazing geology ranging from Badlands buttes rising up out of the vast grasslands to massive limestone and granite formations covered with Ponderosa Pine in the Black Hills. But South Dakota is also home to an amazing, and equally exciting, variety of gemstones and minerals including several beautiful kinds of agates. In fact, the state gemstone of South Dakota is the gorgeous and rare Fairburn Agate.

Fairburn Agate

Agates develop as silica deposits in cavities or pockets caused by trapped gases in (typically) volcanic host rock. As the host rock cooled and hardened, small cracks developed that allowed the gases to escape. Later these cavities filled layer by layer with fluids that were rich in dissolved silica (chalcedony or quartz) and other minerals. The colors and arrangement of these microcrystalline bands are influenced by pressure, temperature, and mineral content that occurs during the formation of the agate. If the pressures and temperatures changed while the agate was forming, bands and patterns would also change, or another form of silica, macrocrystalline quartz (quartz crystals) would then fill in the remainder of the cavity.

Prairie Agates

Agates in and of themselves are amazing. Unlike other gemstones, each agate is unique. Even slabs cut from the same stone will vary in design, color, and pattern. The most common and distinctive type of agate pattern is called a fortification, where the bands crystallize into concentric layers that follow the shape of the cavity. Some other patterns of solid agates are waterline, tube, eye, plume, and seam. Agates in South Dakota contain all sorts of colors, ranging from earth tones to bright reds, oranges, and purples.

The most famous, and also the least common and most valuable, agate found in South Dakota is the Fairburn Agate. Fairburns are fortification agates and occur in just about every color combination imaginable. Other agates found in the Grasslands and buttes of South Dakota are Prairie Agates, Water Agates, and interesting “Bubble Gum” Agates. Prairie and Water Agates are seam agates, while Bubble Gum Agates are eye agates. The primary area for these agates to be found is a wide band just outside the Black Hills that extends from just east of Rapid City through the Buffalo Gap Grasslands along the White and Cheyenne Rivers into Nebraska. The fabulous TeePee Canyon agate is a fortification agate found on the eastern edge of the Black Hills.

Fairburn Agate Beds

Fairburn, Prairie, Water, and Bubble Gum Agates all can be found in agate beds scattered throughout the Buffalo Gap National Grasslands. Here, multicolored hills and buttes of volcanic badlands rise up out of the prairie, covered with pebbles that have been left behind as the surface layers erode away. Amidst all these pebbles can be found Prairie, Water, and Bubble Gum agates, as well as the elusive Fairburns. Beautiful quartz, rose quartz, and smokey quartz pebbles can also be found here, along with an occasional fossil. Three of the most productive locations for Fairburns and their counterparts are the Agate beds at Fairburn, Railroad Buttes, and Kadoka.

Railroad Buttes

We also spent some time collecting in agate beds located along Hwy. 44 just west of Interior. Here we also found some fossil agates and some petrified wood. The fossil agates we found were of three different types. Some had imprints of shells in them, some had agatized fossils embedded in them, and we also found some absolutely gorgeous petrified and agatized corals. The petrified wood we found at this site was mostly black, white and gray with some pinks and oranges mixed in. Some of the pieces had obvious bark on one side. There were other pieces that were solid black. This site on Highway 44 is especially picturesque with multicolored hills comprising the landscape and the peaks of the Badlands in the distance. Camping is allowed on the site so it makes for a really memorable excursion.

Heading west from the Badlands, TeePee Canyon Agates are fortification agates found in the eastern edge of

TeePee Canyon Dig Site

the Black Hills near the SD/Wyoming border. TeePee Canyon agates are characterized by intense patterns of purples, reds, and oranges encased in a chocolate brown limestone host rock. TeePee Canyon agate nodules are found in exposed seams of rock in the TeePee Canyon area of the National Forest just off of Highway 16 west of Custer. Unlike Fairburns and other Grasslands agates which are found on or embedded in the surface of soft tuff, TeePee Canyon agates are located several feet down within the brownish limestone and must be chiseled, chipped, dug, and otherwise broken free. The extra effort is worth it, though, for the sheer beauty of these stones.

TeePee Canyon Agate

If you are heading through the western part of South Dakota, your trip would not be complete without stopping to collect some of these beautiful gemstones along the way. To get to the Fairburn Agate Beds, take Hwy. 79 North from Hot Springs or South from Rapid City and Custer areas. There is turn off for French Creek Road, Hwy 18, which is marked with a sign for the town of Fairburn. This is a gravel road, but well maintained. Once in the town of Fairburn, head through town to where the road heads out of town to the east. Travel this gravel road NE for twelve miles out to the Badlands, the agate beds, and Buffalo Gap National Grasslands French Creek Campground. The Agate Beds are located behind the campground and across the creek. Follow the 4-wheel drive road to the rock collecting area.

Agate Beds off Hwy. 44

The Railroad Buttes collecting area is located east of Rapid City off of Highway 44. Take Hwy. 44 east to the intersection for New Underwood. Turn south onto this road, and travel it across Rapid Creek and through the small town there. You will see Railroad Buttes rising up in the distance from Hwy. 44. Keep traveling on this gravel road until you arrive there. There is a large flat area for parking or you can drive into the agate beds. Two other agate beds are located off of Hwy. 44 near Interior. Contact us through our website for information on these locations.

To get to the TeePee Canyon site, drive west on Hwy. 16 to Forest Service Road 282, about 3 miles west of Jewel Cave National Monument. Turn north on 282, and drive about a mile or two. Dig sites are located on the slopes of the hills in the National Forest.

Hwy. 44 Agate Beds

Camping is allowed at all sites in the Buffalo Gap National Grasslands. French Creek Campground has fire pits and a pit toilet, however Railroad Buttes and the other sites on the Buffalo Gap Grasslands are primitive camping only with no facilities. Be sure to take plenty of water, food, and gear as this is a harsh and rapidly changing environment. There is no shade, and temperatures can get into the 100's on a summer or early fall day. It is not recommended to drive or camp on these sites in wet weather. The roads become soft clay and will bog down even the best of 4-wheel drive vehicles.

Bubble Gum Agates we collected

To purchase South Dakota agates and other rocks, minerals, and gemstones, go to our website www.RocksInMyHead.com. We have a nice selection of Fairburn and TeePee Canyon agates, as well as Prairie, Water, and BubbleGum agates. We will be open in Quartzsite in November at A37 in Rice Ranch, but you can order over the phone (605-376-8754) and by email through the website until then. Happy prospecting and see ya in Quartzsite!