Natural Science in Archaeology

76 4 Lithic Materials
source on the basis of color” assertion that was common in North American archaeology
for many decades. That the authors begin with a thorough review of the geology may be
a fortunate trend. Earlier, in a comprehensive work on the mineralogy of Connecticut
(USA) stone artifacts, Jackson (1940) identified flint, felsite, slate, basalt, coral, and
possibly gabbro. Thus, we do have lithology data for some archaeological contexts.
It would take several volumes to discuss the chipped and ground stone industries
of the world. Major volumes on regional lithic industries include:
Near East: Gebel and Kozlowski (1994)
North America: Butler and May (1984)
Central and South America: Hester and Shafer (1991)
Ural Mountains: Zaykov et al. (1999)
Some of these volumes, or chapters within volumes, do a creditable job with
lithologies; others barely mention what the implements were made of.
4.2 Microcrystalline Quartz
There is much confusion in the literature concerning the origin of the terms “chert,”
“chalcedony,” and “flint,” their exact meaning, and the differences among them. In
my view, chert is cryptocrystalline or microcrystalline quartz of roughly equidimensional
crystals. Chalcedony is microcrystalline quartz with a fibrous structure that
gives it its distinct greasy luster. I suggest the term “flint” should be reserved for
the black, very dense, cohesive nodules that occur, for example, in the Cretaceous
chalks of England. Readers will find, however, that the term “chert” has been
applied to numerous materials. Chert and related high-silica rocks are quite widely
distributed throughout the world. These high-silica rocks were among the first lithic
materials utilized in the Paleolithic for scrapers, borers, adzes, axes, and projectile
points. The compactness, cohesion, hardness, conchoidal fracture and durability of
chert have made it the lithic material of choice across space and time. When there
is not a local source exchange can provide the desired material. An example can be
seen in the islands of the Kodiak Archipelago of the North Pacific where exchange
with the mainland across 50 km of open water was necessary. (Fitzhugh 2004)
Few areas of lithic nomenclature are as confusing as the names for the finegrained
varieties of quartz (SiO 2 ). Quartz is important because rocks and minerals
composed chiefly of quartz make up a large percentage of lithic artifacts. Quartz
is one of the most stable of all minerals under sedimentary conditions and in the
earth’s surface environment. Chert has been used as a general term for fine-grained
siliceous rock of chemical, biochemical, or biogenic origin. It is usually a very hard
(quartz has a Mohs hardness of 7) compact material that fractures conchoidally
when struck. Chert utilized as a lithic raw material has this conchoidal fracture,
but many cherts have a splintery fracture. Grain size also has a significant effect on
fracture properties. Chert is found in many colors: white (novaculite), gray, green,
bluish, pink, red (jasper), yellow, honey-colored, brown, and black.