Lithic Materials
This site is proposed as a reference to characterize the known lithic materials of Mississippi. In archaeology, lithics are stone artifacts that have been purposefully modified, or worked, by human hands. In this science, where anthropological theory of pre-historic cultures is pondered and debated largely on the examination of worked stone objects, an understanding of the presence and source of naturally occurring stones or native materials throughout the local geology is an important piece of information when investigating pre-historic sites. Understanding the source of these native materials provides the archaeologist insight into the relationship of past cultures with their available geological resources and how that relationship may have evolved over time. In addition to this site, the Surface Geology staff has published a map of the sources of lithic materials: Fact Sheet 3: Mississippi’s Native Lithic Material Sources Map. Discussions of anthropology are avoided except where absolutely necessary. Thus, it is important for the reader to understand this site does not indicate occurrences of lithic materials, only the sources of lithic materials that may occur anywhere in the state. Some of these materials may have been traded in from sources outside of Mississippi such as Arkansas Novaculite. It is the task of the archaeologist to identify the source of the lithic materials found on any site. Click the links below to see more information and photograph of a particular lithic material. Click on the photographs to view them in high resolution.
Paleozoic Cherts
Chert is microcrystalline quartz that forms from the migration, condensation, and precipitation of silica in limestone. This geochemical process results in silica crystalizing in ancient limestones in the form of nodules or, in some cases, entire beds. Chert is only found on outcrop in Mississippi in the Paleozoic limestones of Tishomingo County. These limestones are the Ft. Payne Formation and the Tuscumbia Formation. On the Geologic Map of Mississippi from 1969, these limestones were grouped as Limestones, cherts, and shale of Meramec, Osage, and Kinderhook age. This grouping was replaced with Ft. Payne and Tuscumbia. The Fort Payne Formation is the oldest of these limestones (~350 million years) and most notably outcrops in Mississippi on Pickwick Lake in Tishomingo County. Cherts such as those found in these formations can be of considerable high-quality.
References: Tishomingo County Bulletin; Mississippi Paleozoic Rocks
Tuscaloosa Gravels
Outcrops of the Tuscaloosa Formation are Cretaceous age chert gravels derived from Paleozoic era limestones that occur along the Mississippi-Alabama border, from Tishomingo County south to Lowndes County. Gravels of the Tuscaloosa Formation are predominantly chert, with lesser occurrences of grainy clasts of metamorphic quartz and white vein quartz that derived from deeper in the Alabama Piedmont. Chert gravels of this formation are derived largely from the erosion of the bedrock of the Fort Payne, Tuscumbia, and Bangor limestones which the Tuscaloosa Formation unconformably on-laps bordering the foothills of the Appalachians and the Gulf Coastal Plain. Gravels from the Tuscaloosa Formation can also be re-deposited to lower elevations into terraces and stream valleys along the Tombigbee River and its tributaries. These chert gravel resources were utilized widely throughout north-central and east-central Mississippi’s Flatwoods region, in the hills of the Wilcox belt, and across the Black Belt region of northeast Mississippi due to lack of naturally-available chert resources occurring in the area. These chert gravels vary naturally in color in shades of tan, red, pink, gray, black, brown, yellow, and white. Tuscaloosa chert gravel clast commonly retain pressure-solution features, called stylolites, from their origins in the bedrock limestone. These occur as zig-zag patterns and are typically infilled with secondary quartz or chalcedony minerals. These flaws in the rock often cause problems during the manufacturing of stone tools by in Mississippi pre-historic peoples. Heat-treating to better the stone was a common practice for processing Tuscaloosa gravel. Heat-treated Tuscaloosa chert gravel typically exhibits a distinctive red and pink mottled appearance and can strongly contrasts the stylolites in the stone.
References: The Upper Cretaceous Deposits of Mississippi Bulletin; Tishomingo County Bulletin
Tallahatta Orthoquartzites
Tallahatta Quartzite was mined heavily during pre-historic times in east-central Mississippi and traded across much of the state and into parts of Louisiana. It is characterized by silica-cemented, nearly pure quartz sand. Mineral impurities such as glauconite and mica, as well as rare marine fossil imprints such as shells and sharks teeth can be found in the same layers in which the quartzite occurs. These impurities can manifest as inclusions in the quartzite. These inclusions can assist the archaeologist in identifying the quartzite. Tallahatta quartzite is often translucent and can vary in color from white, green, reddish-brown, to black. It often varies in stability and weathers to sandstone or sugar-quartz in artifacts on pre-historic sites. Sometimes these lithics remain stable and retain their glassy appearance. This may be due to the varying stability of the silica cement or the inclusions of glauconite that weathers easily when exposed on fresh fracture surfaces. Lithic-quality Tallahatta Quartzite in Mississippi occurs in the Basic City Member of the Formation along the outcrop belt from Neshoba County to the Alabama line, with concentrations of pre-historic quarry sites along the Chunky River and it’s tributaries in Lauderdale County. Preferred use of Tallahatta Quartzite by prehistoric peoples goes back as early as the Paleolithic cultural period, as other geologic materials for tool making, such as chert resources, are absent throughout much of east-central Mississippi. Due to its abundance, knapping qualities, and the esthetics of the stone, Tallahatta Quartzite has a wide distribution among prehistoric peoples across much of the region and farther south and west across Mississippi, and even into the Mississippi River Alluvial Plain of Arkansas and Louisiana.
References: Mississippi Geology 14,4; Mississippi Geology 13,3; OFR 284 Geologic Map of the Deemer Quadrangle; Geologic Study Along Highway 80 from Alabama Line to Jackson, Mississippi; Geologic Study Along Highway 45 from Tennesse Line to Meridian, Mississippi; Newton County Bulletin; Lauderdale County Bulletin; Clark County Bulletin
Tallahatta Agates
Tallahatta Agate is opaline-rich chalcedony found in the Basic City Member of the lower Eocene age Tallahatta Formation in east-central Mississippi and west-central Alabama. This high-quality lithic material is found associated with occurrences in outcrops of Tallahatta Quartzite as mineralized fillings of joint fractures, fossil burrow casts, and mollusk fossil molds. The stone is translucent in most circumstances and owes its variation in color to minor impurities. The natural occurrence of Tallahatta Agate is scarce and therefore constitutes a rare occurrence in the archaeological record, but its distribution may coincide with that of Tallahatta Quartzite. Tallahatta Agate is remarkably similar in appearance to Florida’s intensely-utilized Agatized Coral.
References: Mississippi Geology 14,4; OFR 284 Geologic Map of the Deemer Quadrangle; Geologic Study Along Highway 80 from Alabama Line to Jackson, Mississippi; Geologic Study Along Highway 45 from Tennesse Line to Meridian, Mississippi; Newton County Bulletin; Lauderdale County Bulletin; Clark County Bulletin
Kosciusko Orthoquartzites
The sandy basal portion of the Eocene age Koscuisko Formation locally contains good quality orthoquartzites. Most noteworthy are outcrops in the vicinity of the town of Kosciusko in Attala County. Ledges of orthoquartzites have been noted in the Koscuisko Formation across the outcrop belt from Montgomery to Newton Counties near the contact with the underlying Zilpha clays. These typically fine-grained quartzites are very hard. Kosciusko quartzite is typically gray in color and is sometimes marbled with a light red iron staining. They can be differentiated from other orthoquartzites in that the cementation is a product of interlocking of sand grains due to quartz overgrowths. They sometimes can only be distinguished from chert by microscopic inspection of the stone.
References: Attala County Bulletin
Cockfield Orthoquartzites
Ledges of orthoquartzites have been noted in the lower sands of the Eocene age Cockfield Formation in a small string of outcrops along the edge of the loess bluff line just beneath the Pre-loess Terrace Deposits in Holmes County near Tchula. This fine-grained quartzites is a product of interlocking of sand grains due to quartz overgrowths. It is gray in color and in some cases marbled with a light red iron staining and very similar in appearance to that of Kosciusko quartzite. This resource likely saw only limited to local cultural utilization.
References: The Claiborne Bulletin
Glendon Limestone
Limestones of Tertiary, Cretaceous, and Paleozoic Formations throughout the State have been locally utilized for grindstones, hammer-stones, plummets, pipes, boat-stones, banner-stones, etc. They can be traced to back to their outcrop of origin by the foraminifera and other diagnostic fossil content.
References: Marls and Limestones of Mississippi Bulletin; Cement and Portland Cement Materials of Mississippi Bulletin; Mississippi Agricultural Limestone Bulletin; Lower Oligocene Gastropoda, Scaphopoda, and Cephalapoda of the Vicksburg Group in Mississippi; Lower Oligocene Bivalvia of the Vicksburg Group in Mississippi
Catahoula Orthoquartzites
The character and unstable nature of Catahoula Quartzite is similar to that found in the Tallahatta. Catahoula Quartzite can be differentiated from similar Tertiary orthoquartzites in Mississippi, such as Tallahatta Quartzite, by the presence of black, angular chert sand grains or the presence of chert and quartz pea gravel inclusions. This can give the stone a salt-and-pepper appearance on the weathered surface. Tallahatta Quartzite conversely often has inclusions of glauconitic grains. The mineral, glauconite, is a silicate of iron that is often green in color and is fairly unstable and susceptible to chemical weathering, leaving the Tallahatta quartzite riddled with small pits or vugs and white snowflake patters around the pits once occupied by the glauconite grains.
The Catahoula Formation outcrops in a broad band throughout south-central Mississippi from Claiborne to Wayne County. The shallow marine to deltaic deposits of the Catahoula are overlain by similar lithologies of Hattiesburg Formation and unconformably unerlain by the limestones and marls of the Vicksburg Group. The Catahoula Fm. is comprised of alternating beds of sandstone, siltstones, and clay. The occurrences of hard sandstones exist throughout much of the outcrop belt of the formation across the state locally due to an abundance of opaline cement in the formation. In certain geological settings, greater concentrations of opaline cement within the sandstones form orthoquartzites in the Catahoula. Occurrences of Catahoula Quartzite seem to be isolated to the western portion of the Formation’s outcrop belt. It has been described as far east as Rankin County along the outcrop belt, but occurs more abundantly in Copiah, Hinds, and Claiborne counties. Fresh and un-weathered Catahoula Quartzite has a vitreous texture and, in many cases, it is translucent. It may be colorless, gray, tan, or black. No matter what color the fresh quartzite was, it typically weathers to white sandstone with the cement having the appearance congealed milk or it may devitrify completely and become chalky. Some occurrences of this quartzite tend to be more stable than others and this high degree variability can commonly be seen over a single geological exposure.
Quartzites in the Catahoula Formation are stable in the phreatic zone (below the water table) and weather to a friable sandstone in the vadose zone (above the water table). Quartzite typically occurs along the western portion of the formation’s outcrop belt in stream channels, along low valley walls, and on hills having a perched water table. The quartzite may also be seen as cobbles, where it has been reworked into stream alluvium that dissects the formation.
References: Claiborne County Bulletin; Hinds County Bulletin; Rankin County Bulletin; Copiah County Bulletin
Hattiesburg Orthoquartzites
This is a quartzite-bearing siltstone found only in the Hattiesburg Formation. This material was found in a single cluster of pre-historic quarries along the valley of the Homochitto River in Franklin County. This is an excellent quality knapping material when fresh and is dramatically different in appearance from other quartzites found in the State. It is light gray in color and, though the material can be dotted with visible pores, it has a clean, regular fracture pattern comparable to other high-quality knapable stones. Hattiesburg Quartzite weathers to pale grey, fine-grained sandstone.
The Hattiesburg Quartzite is a Miocene age orthoquartzite and it is characterized as a hard, gray-colored, opal-cemented, qaurtzitic siltstone or fine-grained sandstone. This material commonly contains numerous dissolution vugs that are often hollow or opal-filled. Fresh Hattiesburg Quartzite exhibits an excellent conchoidal fracture. In artifacts, the stone may weather, differentially or completely, to a friable, light gray to white colored, fine-grained stone that may be uniform or slightly marbled in appearance. In some cases, the weathered material is mottled pink or purple. The only known outcrops of Hattiesburg Orthoquartzite are located along the Homochitto River Valley in southern Franklin County, much of which shows signs of extensive quarrying. Little is known about the cultural context from the debris at these quarry sites, or from the nearby material-reduction sites associated with these quarries. This is due to the general lack of culturally diagnostic artifact at these types of sites. Also, not much is known about the cultural distribution of Hattiesburg Quartzite due to lack of identified samples in other previously recorded artifact assemblage. Fragments of Sioux Quartzite hammer stones (likely from the gravels of the Homochitto River) have been found at Hattiesburg Quartzite quarry and reduction sites and were probably utilized to quarry and process the raw Hattiesburg Quartzite.
High Terrace Gravels
Sand and gravel deposits of multiple age terrace units, once mapped Citronelle Formation, cover much of the south-central third of Mississippi. These deposits are benched at approximately 400 feet above sea level in the vicinity of Crystal Springs in Copiah County and at succeeding lower intervals south to Pearl River County, and at even higher elevations in Hinds, Rankin, and Smith counties. These gravels dramatically decrease in abundance, size, and quality southeastward. They consist predominantly of ancestral Tennessee/Ohio River system gravels which is predominantly honey-colored chert (often containing Paleozoic fossils) but also it also contain quartzite, agate, carnelian, jasper, and petrified wood. The terraces blanket large areas throughout the southern third of the state but the gravel resources are confined to the basal portions of the units and are masked by finer-grained sediments higher in the section throughout the areal extent of terrace. Gravels from these terraces can be found re-deposited at successively lower elevations in river terraces and modern stream valleys.
References: Copiah County Bulletin; Rocks and Fossils Found in Mississippi’s Gravel Deposits
Ironstone
Many of the formations and terrace deposits throughout Mississippi contain ironstone in the form of some combination of ferruginous sandstones, siltstones, or conglomerate cemented by limonite, siderite, or goethite. Knapping-quality and carved ironstones have been recorded from various pre-historic archaeological sites throughout the State. They were often utilized where chert-bearing gravels of suitable size and quality are scarce or where high-quality ironstones were readily available.
Limonite, goethite, and siderite cemented ferrugenous sandstones and claystones are earthy, sedimentary ironstones common throughout Mississippi. These ironstones are typically soft and easy to work materials. Naturally occurring ironstones saw widespread cultural utilization by prehistoric peoples as peck, ground, and even polished artifacts. A goethite-cemented quartzite (ferruginous orthoquartzite) was extensively quarried for its knapping qualities in southeast Mississippi from stream terraces along the lower Leaf and Chickasawhay River watershed. A ferrugenous orthoquartzite is and ironstone sufficiently cemented to break preferentially across the quartz grains to exhibit predictable subconchoidal fracture. Ferrugenous orthoquartzite has a concentration of occurrence on prehistoric Native American archaeological sites in Wayne, Greene, Jones, and Perry counties in southeast Mississippi. The utilization of ferrugenous orthoquartzite had a long tradition which began as early as Dalton projectile point tradition (ca. 10,500 to 8,500 years ago), and likely continued to the Woodland cultural period (ca. 3,000 to 1,000 years ago), as more suitable material became necessary for production of ever smaller projectile points for use in bow and arrow. Ferrugenous orthoquartzite is generally considered a poor quality material but was extensively utilized because a naturally-occurring resource of higher quality chert gravel is lacking in southeast Mississippi. The dominant lithic material (artifacts made from stone) on archaeological sites in southeast Mississippi is typically Tallahatta Quartzite from Basic City outcrops well to the north of this region, and limited resources can also be found locally as float in the alluvium of the Chickasawhay River. Also common, are lithics made from higher-quality chert gravel derived from terrace outcrops further to the west, and milky quartz from terrace gravel from piedmont-derived resources further east in south Alabama.
References: Preliminary Report on Iron Ores of Mississippi Bulletin; Lafayette County Iron Ores Bulletin; Webster County Iron Ores Bulletin; An Investigation of Mississippi Iron Ores Bulletin; Wayne County Bulletin
Limonite
Limonitic claystone is a common natural occurrence throughout much of the surface geology exposures in the coastal plain. It specifically occurs at the contacts between beds of sand and clay. Iron mineral-rich groundwater moving through the sand beds infiltrate the adjacent clay bed. The tiny clay particles in the clay bed are cemented together as iron-oxide/hydroxide precipitate out forming the mineral limonite. Because of the varying bedrock chemistry and iron content of the water, limonitic claystones can differ highly in color from tan, brown, red, orange, pink, and purple (when a manganese oxide called pyrolusite is also present). Differences in color can also bring out the finely-laminated sedimentary layers in the stone. Layers with a higher silt content have more pore-space for limonite to deposit in and can they appear darker in color. These mineralized layers of limonitic claystone are typically more resistant to erosion than other unmineralized layers in the surrounding geology. Therefore, they are readily identified and easily accessible as ledges along stream channels, along valley-walls, and on hillsides/tops in various terrain of the eroding bedrock. Limonitic claystones were a natural resource highly-utilized by Mississippi’s prehistoric inhabitants. It could be ground for ochre or easily carved for use in implements, tools, or ornaments.
Petrified Wood
Many of the formations, terraces, and alluvial deposits in Mississippi contain petrified wood of varying quality. It is often exposed by erosion and redeposited into stream and river valleys. Quality specimens of petrified wood can be found in several different deposits throughout the state. It occurs in abundance, particularly in the Wilcox, Forest Hill, and Catahoula formations, as well as, in the pre-Loess and other terrace deposits throughout the State. Petrified wood was often used to some degree where it was readily available or where other suitable materials were scarce. It is usually easy to identify because the wood grain in most cases is left intact throughout much the rock. Various types of petrified wood, including fossil palm, have been identified on various pre-historic archaeological sites in Mississippi. Fossil palm is commonly derived from Oligocene age strata in the southwestern part of the State, primarily the Forest Hill and Catahoula formations.
References: Mississippi Geology 10,1; Mississippi Geology 2,4; Mississippi Geology 4,2; Mississippi Geology 11,2; Mississippi Geology 2,2; Mississippi Geology 9,3
Pre-loess Terrace Deposits
Pre-loess gravels can be found underlying Pleistocene age loess. These Pleistocene age ancestral Mississippi River terrace deposits parallel the Mississippi River Alluvial Plain from Desoto to Wilkinson County. Pre-loess gravels can contain clasts many times larger than those of the higher terrace gravels mapped as Citronelle to the east. Aside from chert, the Pre-loess gravels include an unusual variety of rocks types different than typical gravel deposits of the gulf coastal plain and including St. Francis Mountain rhyolites, purple-banded Sioux Quartzite, geodes from the Keokuk, Missouri lace agate, Lake Superior agate, large cobble size quartz clasts, large tabular Paleozoic sandstone clasts, and various types of jasper. The pre-loess gravels can also be found re-deposited in stream terraces and in the deeply incised stream valleys dissecting the loess bluffs.
References: Claiborne County Bulletin; Hinds County Bulletin; Rocks and Fossils Found in Mississippi’s Gravel Deposits
Sioux Quartzite
The Sioux Quartzite is a Precambrian metaquartzite found in ancestral Mississippi River terraces, termed the “pre-loess” gravels, which underlie Mississippi’s western loess belt. The source for the quartzite is in the bedrock of Missouri River drainage in South Dakota and southwestern Minnesota. Similar bedrock material can also be sourced north, from the Baraboo Ranges in south-central Wisconsin. It is characterized by a hard, pink to dark purple, often banded quartzite which is fine to coarse-grained, and may contain quartz gravel inclusions or be brecciated. The quartzite may be seen in gravels as cobble to boulder-sized clasts, where it has been reworked into stream alluvium that dissects the pre-loess gravels. It has an irregular to sub-conchoidal fracture, which makes it poorly knappable, though it can be ground and polished into tools and ornaments. It is ideal hammerstone material for its superior durability and commonly large clast size. Its preferred use for quarrying Hattiesburg Quartzite, in Franklin County, was inferred were numerous broken fragments of Sioux Quartzite hammerstones were observed at a heavily worked outcrop.
Igneous Rocks
The closest exposures of bedrock sources for igneous rocks from Mississippi is the ancient volcanic complex of the St. Francois Mountains in southeastern Missouri. During the episode of Kansan glaciation, deep back in the mid-Pleistocene, glaciers plowed through Missouri. Meltwaters and ice-dam breaks carried a flood of igneous rocks from the St. Francois region (along with chert gravel and a host of other materials from the mid-continent) down the ancestral Mississippi River. Subsequent glacial episodes caused the Mississippi River to cut a deeper valley, abandoning remnants of the old one’s courses perched high along the bluffs, leaving behind the Pre-loess Terrace gravels. St. Francois igneous rocks particularly common in the Pre-loess Terrace gravels are rhyolite, trachyte, welded tuff and significantly less common is diabase. Much later, at the end of the last ice age, the ice sheets receded for the last time into the arctic and the Mississippi River filled its valley with sediment to where it is today. Igneous rocks (typically granite and basalt) were then added all the way from bedrock sources in Canada to the modern Mississippi River’s alluvium. These Canadian igneous materials can be seen today along the Mississippi River gravel bars and in irrigation wells drilled into the alluvium but are curiously absent from the older Pre-loess terrace gravels in the adjacent bluffs. Pre-historic cultures widely exploited the igneous materials from the bedrock of Missouri’s St. Francois region far and widely traded throughout mid-continent and across the southeast. Much of the exotic igneous material from the St. Francois region that can be found as artifacts on pre-historic archaeological site here in Mississippi could very well have been trade from the original bedrock source. Though, studying the geologic record tells us that identical material is also available here in the Loess Bluff region and was undoubtedly also exploited. The availability of these resources complicates our understanding of trade in the archaeological record and undoubtedly causes a significant problem interpreting sites here in Mississippi with artifacts made from resources of St. Francois igneous materials.
Mississippi River Alluvium Gravels
Gravel bars along the Mississippi River contain a suite of pebble to large cobble-size clast of various materials form mid-continent bedrock sources. Paleozoic chert gravel makes up the majority of the available rock materials with notable increase in variety and frequency in the component of igneous rocks (most notably Canadian granite) as compared to the ancestral Mississippi River Pre-loess Terrace Gravels of the western Loess Bluff Region. Also notable is the presence of a diverse suite metamorphic rocks in the Mississippi River gravels that are rare or absent from the Pre-loess Terraces, marking a some shift in source material as continental glaciers receded and basin headwater streams became established.
References: 1:100,000 Greenwood Geologic Map; Rocks and Fossils Found in Mississippi’s Gravel Deposits
Cannel Coal
Cannel coal is a type of bituminous coal more accurately classified as a grade of carbonaceous shale. This black claystone is considerably durable compared to other types of coal. It has been exploited worldwide throughout antiquity for both its ease in carving and in maintaining a black, highly-polished surface. In North America, cannel coal comes from Carboniferous age bedrock deposits that are dominated by the fossil plant remains, Lepidodendron and Calamities. The Mississippi River and its northern tributaries drain this Paleozoic bedrock region; therefore, cannel coal can commonly be found as a resource amongst the Mississippi River gravels. Cannel coal’s utilization by prehistoric Native Americans cultures is evidenced by stunning artwork and some unusual utilitarian artifacts found in Mississippi.
Piedmont Quartz
Metamorphic quartz and vein quartz gravel clasts can be found along stream valleys that drain the Cretaceous outcrop in northeast Mississippi belt. These gravels represent a Pleistocene residuum from larger rivers long ago that once drained across the Prairie Region with headwaters that drained the southern crystalline Appalachian Mountains. The clasts are cobble to pebble in size with larger clast-size dominantly being metamorphic quartz with the increased frequency in occurrence south along the Cretaceous outcrop belt. Pediment quartz makes excellent hammerstone material and the vein quartz (milky quartz) component was commonly utilized for projectile points in the absence of locally available chert gravels.
References: The Upper Cretaceous Deposits of Mississippi Bulletin
Clay Resources
Clay from unweathered bedrock sources is typically unsuitable for ceramic manufacturing though some occurrences of deeply weathered bedrock clays are suitable. Kaolinic clay resources for ceramics were utilized chiefly from clay exposures in the alluvium along streams and rivers. These resources can have varying components of silt, sand, and organic impurities even within the same outcrop resource. Certain general geologic inference may be ascertained about the resource utilized in ceramics such as the content of impurities such as loess, mica, or heavy minerals.
References: Clays of Mississippi Bulletin; Pottery Clays of Mississippi Bulletin
Loess Dolls
Loess is a Pleistocene eolian deposit derived from glacial outwash. Loess is typically calcareous with dolomite and calcite. However, the upper portion of loess is highly weathered, leached/non-calcareous, clayey, and has been referred to as brown loam. Loess deposits unconformably blanket the Pre-loess topography with substantial local variation in thickness. In places, weathered loess contains secondary deposits of calcareous concretions referred to as loess dolls or loess kindchen. These limestone concretions are a competent stone source utilized for carved objects such as plummets, pipes, banner stones, etc.
References: Loess Investigations in Mississippi Bulletin
Bauxite
Bauxite is not a true mineral, but a laterite composed of hydrated alumina with variable proportions of iron oxides and hydroxides. It can vary in consistency from a loose clayey aggregate to a competent hard stone. Its unusual textured appearance (technically referred to as pisolitic) and workability of the hard stone variety made it an ideal trade item for the manufacturing of typically ground ornaments by prehistoric peoples in Mississippi. While much of the bauxite on archaeological sites here in Mississippi is typically attributed to outcrops in Arkansas, lithic-quality pisolotic bauxite does indeed occur naturally in Mississippi and was also likely exploited by past Native American cultures.
References: Bauxite Deposits of Mississippi
Authors: Starnes, J., Segrest, B., and Leard, J.
Published: May 2019
Updated: July 2021