Elk Creek Barite, Meade County, South Dakota

Collector's Edge Minerals, Inc. recognizes and thanks the Mineralogical Record for permission to use portions or all of their original article from the "Mineralogical Record", Volume 18, Number 2, pp. 125-130. Authors of the Mineralogical Record, Volume 18, Number 2 article on Elk Creek were Thomas J. Campbell, Donald R. Campbell, and Willard L. Roberts.  Collector's Edge has made some additions and changes to the original article which are incorporated below.

INTRODUCTION:

Collector’s Edge Minerals, Inc., through contractual agreements with one of the local ranchers, has been involved in the mining, collection and preparation of Elk Creek barite for several years, recovering some of the finest barite specimens that have entered the collecting market.  On average only 10% of the concretions mined have barite, and of those, few have what would be considered outstanding specimens.  The effort to break apart the concretions, if not done delicately, can do irreparable harm to barite crystals, if present, which are not only shock sensitive, but heat sensitive as well.  Collector’s Edge has developed specialized diamond saws to open the concretions with minimal impact on the potential crystals within.  Even then, removal and preparation must be done carefully to prevent damage to the barite crystals, and, often, any associated calcite crystals, to ultimately produce a specimen worthy of being placed in one’s collection.

Elk Creek, South Dakota, has long been famous for producing some of the most beautiful, lustrous, gemmy golden barite in the world.

There are two notable occurrences of golden barite in western South Dakota:  Elk Creek in Meade County, and the area around Hoover in Butte County.  However, the barite-bearing unit is observed along the tributaries throughout the following counties including Butte, Custer, Fall River, Meade, Pennington, Perkins, and Washington.  The Elk Creek locality is well known for the fabulous specimens it has produced over the years, and the Hoover occurrence has also yielded some fine specimens, which have a different habit and mode of aggregation.  Specimens of golden barite from South Dakota are much sought after by collectors and are represented in most major museums as well as many private collections.

LOCATION:

Elk Creek is located in Meade County in western South Dakota as illustrated in the map below: 

Exposure of Pierre shale along Elk Creek in Meade County showing some concretion-bearing horizons.

Concretions litter the creek bottom where they have eroded and washed out of the banks.

HISTORY:

Barite has been known from South Dakota at least since Ulke reported it from the Black Hills in 1891.  Dana (1892) described “wine-yellow crystals occupying cavities” in the Badlands.  Specimens almost immediately seem to have found their way into important collections; the Clarence S. Bement collection, for example (which was acquired by the American Museum of Natural History in 1900) contained two Badlands barites (Gratacap, 1912; Conklin, 1986).  Specimens are also mentioned by Ziegler (1914) in his Minerals of the Black Hills.

Willard L. Roberts first collected South Dakota golden barite in 1950 and exhibited specimens at the 1951 California Federation of Mineralogical Societies Show in Oakland, California, and was curator of the Geology Museum at the South Dakota School of mines from 1966 through 1987.  He continued to collect in the Elk Creek, Hoover and other areas (chiefly along tributaries of the Belle Fourche and Cheyenne Rivers) for nearly 25 years, and prepared a thorough documentation of all barite occurrences in the Black Hills (Roberts and Rapp, 1965).

Since the mid-1970s, local ranchers have been reluctant to grant permission to collectors.  Nevertheless, very fine lots of specimens continue to appear on the market occasionally, and collectors willing to persevere will eventually come across fine specimens for sale.

GEOLOGY:

Golden barite occurs at several localities in western South Dakota and is almost entirely restricted to calcareous concretions within the Cretaceous Pierre Shale.  Barite-bearing concretions are found in an arcuate belt around the Black Hills, extending from Buffalo Gap on the southern edge of the hills through Owanka up to and around Hoover.  However, less than 10% of the concretions found within the “barite zone” prove to contain barite when broken open.

At the Elk Creek and Hoover localities barite occurs in fossiliferous, septarian, calcareous concretions.  Concretions are found in several units of the Pierre shale, but at the Elk Creek locality the barite-bearing concretions are found within the Gregory Member.  This stratigraphic unit is characterized by the presence of Baculites gregoriensis.  It is not known with certainty whether the unit hosting the barite-bearing concretions at Hoover is the Gregory Member or not.

In a USGS publication by N.H. Darton (1909), he describes the Black Hills occurrence:

Meade County extends northeastward from the flanks of the Black Hills to the divide between Owl River and Sulphur Creek. To the east it extends for some distance along the west side of Cheyenne River, and it comprises the lower portion of the Belle Fourche Valley.   A wide range of formations is included within its limits, extending from the granites and schists in the Black Hills uplift to the lignite-bearing sandstones and shales in the highlands north of the Belle Fourche. On the slopes of the Black Hills the older rocks are exposed, dipping so steeply to the northeast that within a short distance they are carried to a considerable depth.  The dip diminishes away from the hills and thence, to the northeast, the strata lie nearly horizontal. (Darton, 1909, p. 124)

The Dakota and associated sandstones are exposed in the hogback range, and to the east pass beneath the surface, so that along Belle Fourche River they are at depths of 1,900 to 2,000 feet in the lowlands and of more than 2,500 feet on the divides.  Probably they lie still deeper in the northeastern portion of the county. These sandstones contain artesian water, which enters at an altitude of 3,500 feet or more, so that it has sufficient head to afford artesian flows in the lower lands toward the east. (Darton, 1909, p. 124)

Many thousand square miles of the country adjoining the Black Hills are occupied by the Pierre shale.  This formation is a thick mass of dark-colored shale, weathering light brown, and is relatively uniform in composition throughout.  It gives rise to a dreary monotony of low rounded hills, sparsely covered with grass and not very useful for agriculture. The thickness of the formation is 1,200 to 1,400 feet, so far as can be ascertained, but only at a few places can it be measured.  Where it dips gently away from the hills it is almost impossible to measure the rate of the dip of the shale.  Fortunately it has been found that the formation includes, at a horizon about 1,000 feet above its base, scattered lenses of limestone usually containing numerous shells of Ludna occidentalis. The greater number of these lenses occur at the definite horizon just mentioned, and in some places, where they occupy the surface over a wide area, they throw light on the attitude of the formation.  It is evidence of this sort that provides a basis for the determinations of structure which afford an important part of the data for ascertaining the depth of the Dakota sandstone in the region adjoining the Black Hills. (Darton, 1909, pp.22-23)

The limestone concretions with Ludna vary in size from those of 2 or 3 cubic feet to masses 20 feet in diameter and 6 or 8 feet thick, usually of irregular lens shape.  Owing to their hardness these lenses, when uncovered by erosion, give rise to low conical buttes resembling in form very squat tepees, and accordingly they have been designated "tepee buttes," a term used for similar occurrences in the Pierre shale of southeastern Colorado.  They occur in large numbers in the vicinity of Oelrichs, east of Hermosa and Sturgis, and in the Willow Creek valley, varying in height from 10 to 150 feet above the surrounding slopes. Horizontally the lenses occur at irregular intervals, so that the buttes are scattered very erratically and some of them are separated by many miles. (Darton, 1909, p. 23)

Numerous concretions occur in the Pierre shale at various horizons and usually contain large numbers of distinctive fossils.  Baculites compressus, Inoceramus sagensis, Nautilus dekayi, Placenticeras placenta, and Heteroceras nebrascensis are the more abundant, and Ludna occidentalis is found here and there.  The most fossiliferous horizon is in the upper part of the formation. The concretions are generally small and of a calcareous nature, and they break into brown pyramidal fragments which are scattered more or less thickly all over the Pierre surfaces. (Darton, 1909, p.23)

In the southern part of the Black Hills region there is, at the base of the formation, a very distinctive series of black, splintery, fissile shales, containing three beds of concretions. These shales have been included in the Pierre, though not yet found to contain distinctive fossils;  they may be Niobrara. They are about 150 feet thick in the Edgemont-Oelrichs region, where they give rise to a steep slope, in places rising conspicuously above the lowlands eroded in the Niobrara chalk.  The concretions exhibit a curious sequence. The lower ones are biscuit-shaped, hard, and siliceous;  those in the layers next above are similar in shape and composition,  but are traversed in every direction by deep cracks filled with calcite and locally scattered crystals of barite;  and those in the uppermost layers are large, lens- shaped, highly calcareous, and of a light-straw color, consisting mainly of well-developed cone-in-cone. (Darton, 1909, pp.24-25)

Chart illustrating the geology, including the Pierre Shale formation.  From the Department of the Interior, USGS, Water-Supply Paper 227, by N.H. Darton, 1909, p.8.

Elk Creek:

A popular area for good barite occurs in Meade County along a significant length of Elk Creek from the Cheyenne River west for approximately 30 kilometers.

Along Elk Creek, limestone concretions are found in at least four distinct horizons.   Generally, the best horizon is the lowermost one that occurs at or near the creek bottom.  Since the bedding is essentially horizontal, this lower horizon can be traced for some distance within the draws.  Potential barite-bearing concretions can be characterized as oblate spheroids 1 to 3 meters in maximum dimension; they are septarian, fossiliferous and partially hollow.  Septa are composed of yellow calcite.  Invertebrate fossils found in the concretions include the cephalopods Baculites gregoriensis, Eutrephoceras dekayi, Placenticeras meeki and the bibalve Inoceramus labiatus.  Other invertebrate fossils have also been found.

An 18" diameter ammonite discovered in the same location as the barite-containing concretions.

Barite occurs as colorless, yellow, amber or deep golden brown, transparent crystals that are elongate parallel to [010] (Roberts and Rapp, 1965).  Length to width ratios vary between 2 to 1 and 7 to 1, resulting in stubby to elongate prismatic crystals.  Dominant forms are those of the unit prism and dome. Roberts and Rapp also noted that the dome faces on some crystals are curved right, left, backwards and forwards.  These faces may also be rather bumpy and upon close inspection these “bumps” actually represent numerous growth hillocks which may indicate stress within the crystal structure.  This is supported by the extreme sensitivity these crystals have to abrupt temperature changes (e.g., handling a cool crystal with warm fingers); the crystal will immediately fracture internally.  Nevertheless, Sinkankas (1959) reports that Elk Creek barite has been more successfully cut and faceted than barite from other localities because the crystals are far less inclined to split.

Crystal drawings depicting (left) one habit of barite from Elk Creek (Roberts and Rapp, 1965) and (right) the more typical, tapered, chisel-point habit from Elk Creek (Sinkankas, 1959).  (b axes vertical)

Both dome and prism faces may be slightly striated or etched, resulting in a very dull luster.  Despite these irregularities, faces on the majority of crystals are very lustrous and mirror-like.  Crystals are commonly 2 to 8 cm in length, 1 to 2 cm in width, and tapered toward their terminations.  The largest crystal reported from Elk Creek measures 30.5 cm in length and 17.5 cm in circumference and is in the collection of the South Dakota School of Mines and Technology geology museum.  Barite from this locality fluoresces and phosphoresces bright yellow-white under shortwave ultraviolet radiation (Roberts and Rapp, 1965).

Crystal drawing depicting a typically twisted and distorted rhombohedral crystal of yellow calcite as is commonly associated with barite at Elk Creek (Roberts and Rapp, 1965).

Barite crystals are commonly found implanted on beautiful yellow to yellow-orange calcite.  Aside from providing a nicely contrasting background, the morphology of the individual calcite crystals is unusual.  Crystals are composed of the simple rhombohedron but are quire distorted.  In some crystals the rhombohedron is elongated parallel to a rhombohedral face “so that it suggests an elongate monoclinic prism” (Roberts and Rapp, 1965).  Other crystals are also elongated but distorted in two directions.  In these crystals, “the terminal and elongated faces are curved as though a torsional pull had elongated the crystal and had twisted in on its long axial” (Roberts and Rapp, 1965).  Individual calcite crystals range in size from 3 mm to 2.5 cm.  In addition to calcite, barite at Elk Creek may also be associated with gypsum which occurs as very slender, 1 cm, white, prismatic, twinned crystals, and less commonly as well-formed, colorless, prismatic crystals.  Barite is rarely associated with whewellite.

Hoover:

Near Hoover, along the South Fork of the Moreau River, barite occurs in concretions very similar to the ones described above from the Elk Creek locality.  It is not known, however, if the species of cephalopods within the concretions are the same.  Barite occurs as colorless, white, yellow or golden yellow-brown, transparent, slender, prismatic crystals composed of the unit prism and dome.  The majority of crystals are different from those found at the Elk Creek locality in that they are markedly elongated parallel to [010] with a length to width ration of approximately 10 to 1.  In addition, crystals from Hoover tend to occur in divergent sprays and radial aggregates up to 25 cm across.  Individual crystals range from < 1 mm up to a maximum of about 15 cm.  Some, however, are very similar to the stubby, prismatic crystals from Elk Creek but rarely exceed 2 cm in length.  Barite crystals are either perched on yellowish, 2 to 4 mm, calcite crystals, on a brown to gray-black, smooth so somewhat bubbly surface of calcite that forms a thin rind on the limestone surfaces within the bugs of the concretions, or on stalactitic to finger-like growths of calcite.  A second generation of calcite is occasionally found in some concretions as colorless to very pale yellow, flattened rhombs or as spherical aggregates.  

Barite:  BaSO4

Golden barite from the Elk Creek and Hoover localities was examined chemically by atomic absorption methods using a Perkin-Elmer model 3030 atomic absorption spectrophotometer utilizing a nitrous oxide-acetylene flame.  One representative sample for analysis was prepared from each locality. 

A partial analysis of the Elk Creek  barite sample yielded BaO = 63.71, CaO = 0.07 and SrO = 0.08%.  The Hoover sample yielded BaO = 61.70, CaO = 0.06 and SrO = 0.45%.

Collector’s Edge has been involved in the mining and preparation of barite specimens for several years.  These operations include use of large excavation equipment to retrieve the large concretions and hand labor and specialized cutting equipment to carefully open up the concretions to retrieve any barite crystals.  The following pictures are a compilation of photos taken during these mining operations.

Excavator removing concretions from the concretion-bearing horizons which can be seen in the horizontal layers above the excavator.

A Collector’s Edge diamond chain saw being used to open up a concretion that has been placed on the bank by the excavator.

Close-up of interior of a concretion with a nice, lustrous barite crystal surrounded by honey-colored calcite crystals.

Portions of concretions arriving at the Collector’s Edge laboratory for future preparatory work.

A portion of a concretion at the Collector’s Edge preparation laboratory for eventual preparatory work. This unit produced some spectacular barite specimens.

Deep brown, gemmy group as-received barite crystals on calcite matrix requiring laboratory preparation.

Part of a concretion containing a cluster of barite crystals as received at the CEMI laboratory.

A very nice group of barite on a part of a concretion.

A spectacular, large barite crystal on concretion. Note, however, that the barite is not associated with the deep yellow calcite crystals some times found with the barite.

Specimens after cleaning and preparation, being readied for cataloguing and pricing.

Two very nice barite specimens.

A superb cluster of barite crystals on honey colored calcite crystals.

Close-up of 12.5 cm-wide barite group on honey colored calcite crystals. Note the clean terminations, dark brown color and clarity of the barites.

Excellent group of barite crystals on honey colored calcite crystal covered matrix.

Close-up of barite crystal on calcite matrix.

Nice cluster of barite crystals on matrix.

Very aesthetic cluster of barite crystals on honey colored calcite matrix.

Close-up of barite crystal cluster on matrix prior to trimming and preparation.

Close-up of barite crystal cluster on matrix after trimming and preparation.

Cabinet specimen (10 cm across) of richly colored golden barite on yellow calcite from Elk Creek.

Nice transparent barite crystal.

An extremely nice barite specimen; the "crack" in the matrix is natural and often occurs in specimens, however, it tends to be stable and does not need repairs.

An excellent specimen of barite.

An outstanding group of barite crystals on calcite coated matrix.

Outstanding group of barite crystals on calcite coated matrix.

 

Outstanding large barite crystal on honey colored calcite crystals.

OTHER MINERALS:

Gypsum:  CaSO.2H20

Gypsum is sometimes found with barite and calcite; it occurs as very slender, prismatic crystals and blocky individuals similar to those from Elk Creek.  Very rarely gypsum is found as small “ramshorn” curls.

Ram’s horn gypsum curl, 3 cm, from Hoover, South Dakota School of Mines Museum of Geology collection.  Tom Campbell photo.

Whewellite:  CaC204.H20

Whewellite is a hydrated calcium oxalate.  It is rarely associated with the barite.

CURRENT STATUS:

The geological extent of golden barite-bearing rock is great, covering a distance of over 150 kilometers, however only those areas exposed by stream erosion have been worked to any extent by collectors.  This is therefore not an occurrence in any conceivable danger of ever being worked out.  However, much labor is involved in finding and cracking open the hard concretions which can reach 3 meters in diameter, and it is very difficult to salvage the fragile and sensitive crystals undamaged.  Furthermore, all collectors should be diligent about obtaining permission from the local ranchers to collect on their lands; they do not take kindly to trespassers.

REFERENCES:

Collector's Edge Minerals, Inc. recognizes and thanks the Mineralogical Record for permission to use portions or all of their original article from the "Mineralogical Record", Volume 18, Number 2, pp. 125-130.  Contributing authors were Thomas J. Campbell, Homestake Mining Company, Exploration Division; Donald R. Campbell, Gencorp Inc., Research and Development Division; and Willard L. Roberts, Museum of Geology, South Dakota School of Mines and Technology.

Conklin, L.H. (1986)  Letters to George F. Kunz.  Privately printed, p. 5-6.

Dana, E.S. (1892)  The System of Mineralogy of James Dwight Dana.  Sixth edition, John Wiley & Sons, New York, p. 904.

Darton, N.H. (1909) Geology and Underground Waters of South Dakota, Department of the Interior, USGS, Water –Supply Paper 227.

Gratacap, L. P. (1912) A Popular Guide to Minerals.  Van Nostrand, New York, p. 306.

Roberts, W.L., and Rapp, G.R., Jr. (1965) Mineralogy of the Black Hills.  South Dakota School of Mines and Technology Bulletin No. 18, 268 p.

Sinkankas, J. (1959, 1976) Gemstones of North America.  Van Nostrand Reinhold, New York; vol. 1, p. 488-490; vol. 2, p. 291-292.

Ulke, T. (1891)  An early checklist of Black Hills minerals.  The Hill City Tin Miner. Reprinted in Rocks and Minerals, vol. 10, no. 8, p. 120-122.

Ziegler, V. (1914) Minerals of the Black Hills.  South Dakota School ofMines Bulletin 10, p. 209