Archaeology Lab (ANTL 207)Introduction to Artifacts

Artifact – anything made, modified or utilized by humans.

Artifacts are material remains left behind by people. They make up one of the most important datasets used by archaeologists to interpret past human behaviour. In the archaeology lab artifacts are divided initially by material type – pottery, stone (lithics), metal, glass, shell, bone, etc. These are the most common artifact categories. Further, more refined categories exist with each of these, as you’ll see below.

Lithics – stones. The term “lithic” comes from the Greek lithos meaning stony. ‘Lithic’ is an adjective, which is why you see the term before the word ‘tool’ or ‘artifact.’ Stone tools are the oldest artifacts that have survived in the archaeological record. Like pottery, stone preserves indefinitely so archaeologists working on prehistoric sites tend to find lots of it. But stone tools have been around much, much longer than ceramic artifacts. In fact, the use of stone tools predates the evolution of modern Homo sapiens by more than a million years. The earliest stone tools come from Olduvai Gorge in Africa and date to approximately 2.5 million years ago (mya). From that time up to the adoption of pottery making around 14,000 B.C. in Japan the archaeological record is dominated by stone.

This isn’t really surprising since humans have long understood the tremendous utility of this unique material – a lump of stone could be worked (flaked/chipped) to create a sharp cutting edge and then re-sharpened many times. Until recently hunting-gathering groups have flaked lumps of stone to create spear points, arrow points (arrowheads), choppers, scrapers, drills and many other lithic tools. Later, farming peoples realized how stone could be utilized to grind grains like wheat and corn, and since the advent of farming in Mesopotamia around 10,000 years ago humans have been creating groundstone tools.

Flaked or chipped stone – rocks that can be flaked (chipped) so that they have a sharp edge include flint, chert, obsidian (volcanic glass), jasper, rhyolite, quartz, quartzite, petrified wood and even glass. The creation of flaked stone objects is a subtractive process, whereby material is removed from a mass of stone. This stands in contrast to ceramic technology, which is additive by nature. The principal goal of lithic reduction for the ‘flintkanpper’ is to fracture the lithic material in a controlled and predictable way in order to a) not waste time and material and 2) achieve the desired shape.

Obsidian blades

Reduction involves the removal of lithic material, usually from a core - the mass of stone from which flakes are removed. There are two basic flaking techniques: percussion and pressure.Persussion flaking – striking the core with a hammerstone or against a fixed stone anvil; reltively large flakes are removed and large flake scars (negative impressions of flakes) can be seen on the core

Direct percussion – the hammer strikes the stone directly Indirect percussion – a bone, antler, or wood punch is placed on an edge of the

core and struck with a hammerstonePressure flaking – steady pressure exerted on a punch to detach flakes; generally small flakes are removed

Chert biface from the Maya site of Lamanai, Belize

Groundstone - A general or catch-all category for stone that is shaped by pecking (pulverizing) or abrading (by grinding, smoothing, polishing and drilling). Some types of stone, such as granite or basalt, will not flake well due to their mineral structure. The softer varieties of such stones, including soapstone (steatite), alabaster, turquoise and lapis lazuli, were (and still are) shaped primarily by cutting methods. Objects made from tough stones, such as granite, can be shaped by pecking – hitting the stone with a hammerstone at approximately a 90° angle to create small pits in the stone. Abrading or grinding creates a smooth, even surface and often involves the use of small, hard particles such as sand as an additional abrasive along with water or oil. It is thought that jade, a mineral harder than steel, was shaped in this manner by precolumbian peoples such as the Maya.

Mano and metate – precolumbian groundstone tools

Jade fragment from the Maya site of Lamanai, BelizeNote the high degree of polishing

Pottery – any type of baked clay containing a tempering agent (aplastic inclusion). So pottery is made up of clay, which is plastic (can be shaped) and temper, the aplastic inclusion. The clay and the temper together are referred to as the paste. Temper is added by the potter to the clay to give the clay greater strength and prevent shrinkage by the wet clay as it dries. Tempering materials or agents include grit (rock fragments), sand, ground or powdered shell fragments, grog (broken pottery) and a variety of organic agents, including Spanish Moss, plant fibers, straw, and other organic materials that burn out when the pottery is fired. Without tempering agents clay tends to shrink and crack during drying and will fall apart quickly after firing.

Once people from different cultures throughout the world understood how to make fired clay containers they usually made LOTS of them. Also, because of how it is made pottery is very durable – it lasts almost indefinitely in the archaeological record. It is for these two reasons that archaeologists often find lots of pottery, and a lot of lab work involves processing and analyzing pot sherds.

In the archaeology lab pottery is classified by paste and surface treatment. Potsherds are broken pieces of a pot. It’s pretty rare for archaeologists to find whole ceramic vessels, unless one is lucky enough to find a tomb. Looters target pyramids in the Maya area and elsewhere because they know that whole ceramic vessels were often interred in the tombs of Maya kings and queens, and these vessels, often with beautiful polychrome (multi-colored) designs and hieroglyphs, can fetch many thousands of dollars on the illicit international antiquities market. So unless you’re excavating a tomb

or have found a cache of vessels more than likely you’ll be bringing back sherds to the archaeology lab.

Pot sherds are usually classified as rim sherds, neck sherds and body sherds, depending on where on the original pot they originated. Rim sherds provide the most stylistic information, since they convey quite a lot about the overall shape of the vessel. The color of the paste and surface of a pot provide information on how the vessel was fired. The shape and temper of a vessel give clues concerning its function; consistency in vessel shape, size and tempering give clues about how a pot was made and how a society is organized. Archaeologists are often obsessive about pottery, in part for the two reasons listed above (there’s often a lot of it made in prehistoric times and it preserves extremely well), but more importantly because a lot of information can be extracted from a single pot sherd.

Drawing of rim of Early Postclassic Period (ca AD 122-1400) ceramic vesselFrom the Maya site of Lamanai, Belize

Historic potsherds -

19th century ceramic artifacts from Nauvoo, Illinois

Precolumbian potsherds -

Ceramic rim sherds from the Maya site of Lamanai, BelizeLate Classic Period (AD 600-900)

Daub is a special category of pottery that was originally clay tempered with grass, straw or reeds, plastered atop a framework of sticks, and allowed to bake in the sun. This framework or latticework of sticks and mud is called wattle and daub architecture by archaeologists. Normally, daub dissolves over the course of time and does not preserve. But if a wattle and daub structure burns the daub is fired by accident and becomes a type of pottery. It then preserves extremely well in the archaeological record.

Metal – metal is found at some prehistoric sites but often is associated mainly with historic period sites. Metals found at archaeological sites include iron, copper, gold silver and lead, among others.

Iron is often very rusty and can be challenging to distinguish from soil using the naked eye. Some of the rust can be removed by brushing, and in most archaeology labs dry brushing is the initial step in processing iron objects such as nails and other hardware. Further processing of iron artifacts requires reverse electrolysis, a technique that lifts rust particles off an object.

Copper is distinguished in archaeological contexts by its green patina, which helps to preserve organic materials the copper touches. Cloth and fibers might be found embedded in copper artifacts, so copper should be checked very carefully once it is brought to the archaeology lab. Copper needs little conservation and the green patina should not be removed unless further conservation efforts are undertaken as the patina actually protects the artifact from further breakdown.

Copper axe in three pieces from the Maya site of Lamanai, Belize

Lead is heavy, soft and does not corrode. It can occur in cubic crystals (galena) or be shaped into bullets, such as the famous minnie balls from the Civil War. Silver and gold are fairly rare, as people were careful to take their valuables with them when they abandoned sites, and sometimes silver and gold were melted down to form new metal objects. Silver is covered with black corrosion, but gold does not corrode. If gold or silver are found at a site or are in an archaeology lab be very careful not to discuss these with people other than archaeologists because if their presence (or even suspected presence) is one of the main reasons archaeological sites are looted and labs are broken into by thieves.

Wood, Bone, Antler and Shell – depending on soil conditions and weathering agents certain sculpted organic materials such as these might be preserved in the archaeological record. Simple digging sticks or clubs may have been the earliest objects created and used by early human ancestors, long before the earliest preserved artifacts, stone tools. Yet the addition of stone tools to the toolkit of our earliest ancestors must have greatly increased their ability to cut and shape larger pieces of wood as well as bone, ivory, antler and shell. As you can imagine, conservation is key to long-term preservation of organic artifacts once they are excavated from the ground or from the sea. Organic materials such as these are best handled by professional conservators, such as those that work at the Getty Institute and the Smithsonian Institution.

Carved (incised) bone tube from the Maya site of Lamanai, BelizeLate Classic Period (ca. 700-900 AD)

Worked (drilled and abraded) marine shell fromthe Maya site of Lamanai, Belize

Glass – glass is melted silica that can be formed into whatever shape is desired by the glassblower. In North America it is found in historic (post-contact) contexts, but in the Old World it dates to the Old Kingdom in Egypt. Glass bottles and other types of vessels can be dated typologically. Over time, water penetrates the interior of the glass, causing the glass to flake into layers – a kind of patina. Left untreated, glass will eventually break down into little flakes.

Wine bottle, early 18th century, Virginia

19th century bottles from Essex, England