James A. Harrell, Ph.D.
Professor of Geology
Department of Environmental
Sciences (Mail Stop #604)
(Mail Stop #604)
The University of Toledo
2801 West Bancroft St.
Toledo, Ohio 43606-3390, USA
Much of what remains of ancient Egypt consists of stone. There are building stones for temples, pyramids, and tombs; ornamental stones for vessels, sarcophagi, shrines, stelae, statues, and other sculptures; gemstones for jewelry; and utilitarian stones for tools, weapons, pigments, and other applications. Still other stones were processed to extract their precious metals. These remains range in age from the Late Predynasic period (beginning about 3200 BC) to the Roman period (ending about 400 AD; Table 1). In common parlance, the term ‘stone’ includes ‘rocks’ as well as the ‘minerals’ they contain. There are three general categories of rocks – sedimentary, igneous, and metamorphic, and these are further subdivided according to their textures and constituent minerals.
Sediments (mud, sand and gravel) deposited on ocean floors and land surfaces are hardened into sedimentary rocks through a variety of lithification processes, including compaction, cementation, and recrystallization. Continental sediments are derived from weathered and eroded pre-existing rocks, and are deposited mainly by rivers but also occasionally by wind, glaciers, and other processes. Marine sediments, in contrast, are composed mainly of biogenic material (hard skeletal parts of algae, protozoa, and especially invertebrate animals) or inorganic precipitates produced by evaporation of seawater, but also sometimes include continental sediments carried by rivers to the seas. Other sedimentary rocks are the result of secondary mineralization of pre-existing sedimentary rocks.
Sedimentary rocks used by the ancient Egyptians include: limestone (from biogenic marine sediments); rock gypsum and rock anhydrite (both from evaporative marine sediments); sandstone, including siliceous (quartz-cemented) sandstone or quartzite (from continental sediments and, in part, shallow nearshore marine sediments); and travertine and chert (both from secondary mineralization of limestone). Nearly all the ancient quarries for limestone, travertine and chert were located in the hills and cliffs bordering the Nile River valley between Cairo in the north and Isna in the south. Some limestone was also quarried along the Nile Delta’s Mediterranean coast near Alexandria. Quarries in the Nile valley from Isna southward into northern Sudan supplied the sandstone. Rock gypsum and rock anhydrite were obtained from Egypt’s Red Sea coast, and rock gypsum also came from the Faiyum in the Western Desert. A beautiful blue rock anhydrite comes from an unknown source and may have been imported into Egypt.
Igneous rocks form through the crystallization of magma (molten rock). They are referred to as ‘plutonic intrusives’ when they form deep below the Earth’s surface, ‘volcanic intrusives’ when emplaced in the shallow subsurface (dikes and related rock bodies), and ‘volcanic extrusives’ when coming from a volcano and deposited on the surface (lava flows, and airborne pyroclastic falls and flows).
Igneous rocks used by the ancient Egyptians include: granite, granodiorite, quartz diorite, diorite, and pyroxenite (plutonic intrusives); andesite and dolerite porphyries as well as other porphyritic rocks (volcanic dikes and lava flows); basalt and obsidian (volcanic lava flows); and tuff and related rocks (volcanic pyroclastics). Apart from the famous granite and granodiorite quarried at Aswan on the Nile River, the igneous rocks came from the Faiyum in the Western Desert (basalt) and especially the mountains of the Eastern Desert (all other rocks, excluding obsidian). Obsidian (volcanic glass) does not occur in Egypt, and was imported from the eastern Mediterranean and southern Red Sea regions.
Metamorphic rocks are derived from pre-existing sedimentary, igneous or other metamorphic rocks through the application of high pressures, high temperatures or chemically active hydrothermal fluids deep below the Earth’s surface. The metamorphosis occurs in the solid state (without melting) through secondary mineralization and recrystallization. The resulting rocks are either foliated, with a parallel alignment or planar segregation of their constituent minerals, or non-foliated.
Metamorphic rocks used by the ancient Egyptians include: anorthosite gneiss and tonalite gneiss (foliated); and marble, metaconglomerate, metagabbro, metagraywacke, serpentinite, and steatite (non-foliated). The anorthosite gneiss comes from the Nubian Desert west of Lake Nasser, and the other rocks were quarried in the mountains of the Eastern Desert.
The other stones employed by the ancient Egyptians are minerals found mostly within the plutonic and metamorphic rocks. These are the gemstones used for jewelry and include: amazonite, a variety of microcline feldspar; emerald, a variety of beryl; garnet; peridot, a variety of olivine; numerous varieties of quartz (agate, amethyst, carnelian and other colored chalcedonies, jasper, milky quartz, and rock crystal); and turquoise. These minerals were quarried in the Sinai (turquoise), St. John’s Island in the Red Sea (peridot), the Nubian Desert west of Lake Nasser (agate, carnelian and other chalcedonies); and the mountains of the Eastern Desert (all the rest). Lapis lazuli, a gemstone rock rather than a mineral, was also widely used in Egypt but was apparently imported from Afghanistan. The plutonic igneous and metamorphic rocks are also the source of much of ancient Egypt’s gold, copper, silver, tin, and some iron and lead, with sedimentary rocks supplying additional copper, iron and lead. All of these were obtained from the Eastern Desert with much of the copper (derived from malachite) also coming from the Sinai.
Plate tectonics and other earth movements in combination with erosion processes have brought the originally deeply buried sedimentary, igneous and metamorphic rocks to the surface in Egypt. The generalized distribution of these rocks is shown by the geologic map in Figure 1. The exposed plutonic igneous and metamorphic rocks, which form mountains in the Eastern Desert, are commonly referred to as the Precambrian ‘crystalline basement’ and in Egypt are over 550 million years old whereas the sedimentary and volcanic igneous rocks are mostly less than 100 million years in age.
For images of many of the stones used by the Egyptians (especially the ornamental varieties) as well as information on the ancient quarries see the author’s web site at http://www.eeescience.utoledo.edu/egypt/.
Limestone and sandstone were the main building stones of ancient Egypt. From Early Dynastic times onward, limestone was the material of choice for pyramids, mastaba tombs, and temples within the limestone region. From the late Middle Kingdom onward, sandstone was used for all temples within the sandstone region as well as many of those in the southern part of the limestone region. Both limestone and sandstone were also employed for statuary and other non-architectural applications, when harder and more attractive ornamental stones were not available. Along the Red Sea coast, the temples and other important buildings of the Ptolemaic and Roman periods were built with the locally available rock gypsum and rock anhydrite.
In contrast to the drab, unpolished building stones, those employed for ornamental applications have attractive colors and patterns, and also take a good polish due to their greater hardness. The principal applications of the various stones and their periods of use are as follows. (1) Exterior veneer on pyramids: Old Kingdom – granite, and granodiorite. (2) Pyramid capstones: Old and Middle Kingdoms – granodiorite, and possibly basalt. (3) Linings of burial chambers and passages in pyramids and mastaba tombs: Early Dynastic period through Middle Kingdom – granite, granodiorite, and siliceous sandstone. (4) Door lintels, jambs and thresholds of temples: Early Dynastic through Roman periods – granite, granodiorite, and siliceous sandstone. (5) Temple pavements: Old Kingdom – basalt, and travertine. (6) Temple columns: Old and Middle Kingdoms – granite. (7) Interior wall veneer, pavement and columns for temples and other buildings: Roman period – andesite-dacite porphyry, granite, granodiorite, metaconglomerate, metagabbro, metagraywacke, pegmatitic diorite, quartz diorite, rhyolite porphyry, tonalite gneiss, and trachyandesite porphyry. (8) Basins: Roman period – granite, andesite-dacite porphyry, and tonalite gneiss. (9) Barque shrines: Middle and New Kingdoms – granite, siliceous sandstone, and travertine. (10) Small statue shrines (naoi): Old Kingdom through Roman period – granite, granodiorite, metagraywacke, and siliceous sandstone. (11) Obelisks: New Kingdom and Roman period – granite; and New Kingdom only – metagraywacke, and siliceous sandstone. (12) Offering tables: Old Kingdom through Roman period – granite, granodiorite, metagraywacke, siliceous sandstone, and travertine. (13) Small vessels and figurines: Late Predynastic period through Old Kingdom – andesite porphyry, anorthosite gneiss, basalt, granite, metagraywacke, obsidian, pegmatitic diorite, quartz rock crystal, red-and-white limestone breccia, rock gypsum, serpentinite, silicified (petrified) wood, travertine (the most commonly used stone), tuff, and tuffaceous limestone; and Middle Kingdom and Second Intermediate period only – blue rock anhydrite. (14) Canopic jars: Old Kingdom through Roman period – travertine. (15) Sarcophagi: Old Kingdom through Roman period – granite, granodiorite, metagraywacke, and siliceous sandstone; Old through New Kingdoms only – travertine; New Kingdom through Late Period only – metaconglomerate; and Late Period only – basalt. (16) Small to colossal statues and other sculptures: Early Dynastic through Roman periods – granite, granodiorite, metagraywacke, red-and-white limestone breccia, siliceous sandstone, and travertine; Old and Middle Kingdoms only – anorthosite gneiss; early New Kingdom only – marble, and pyroxenite; Late Period only – dolerite porphyry; Late through Roman periods only – basalt, and metaconglomerate; and Roman period only – andesite-dacite porphyry. (17) Scarab and shabti figures: New Kingdom through Roman period – metagraywacke, serpentinite, steatite (usually glazed), and travertine. (18) Stelae: Old Kingdom through Roman period – granite, granodiorite, metagraywacke, and siliceous sandstone; and Late Period only – metaconglomerate. (19) Cosmetic and ceremonial palettes: Late Predynastic and Early Dynastic periods: metagraywacke. Note that many of the above objects were also carved from non-ornamental limestone and sandstone.
The many precious and semi-precious gemstones available to the ancient Egyptians were employed primarily for beads, pendants, amulets, inlays, and seals. Agate, amazonite, carnelian (including sard) and other colored chalcedonies, garnet, jasper, lapis lazuli, obsidian, rock crystal and milky quartz, steatite (usually glazed), and turquoise were used from the Late Predynastic through Roman periods. Amethyst was employed mainly during the Middle Kingdom and again during the Ptolemaic and Roman periods. The Romans were the first to use emerald and peridot for jewelry, and also imported into Egypt other gemstones from India, including aquamarine (beryl); carnelian, onyx, sard and sardonyx (all varieties of chalcedony); and sapphire and ruby (corundum).
Perhaps the heaviest used and least glamerous stone employed by the ancient Egyptians is chert, which is also commonly referred to as flint. From Predynastic times onward it was used for tools (awls; adzes, knife and sickle blades; axe and pick heads; choppers; drill bits; and scrapers) and weapons (dagger blades, and spear and arrow points). Even when metals (copper, bronze and later iron) became commonplace for these applications, chert was still a popular low-cost alternative. For tools and weapons requiring the sharpest edges, imported obsidian was employed. A wide variety of stones, especially hard ornamental ones, were used for the heads of maces, a club-like weapon.
From Late Predynastic times into the Late Period, the quarrying and much of the carving of ornamental stones was done with hard, fracture-resistant stone tools known as pounders and mauls. These were primarily of dolerite, but siliceous sandstone, anorthosite gneiss and fine-grained granite were also occasionally used. These same rocks were also employed as grinding stones for smoothing rough, carved stone surfaces. The actual polishing of these surfaces was probably done with ordinary, quartz-rich sand of which Egypt abounds. For the softer sandstone and limestone, picks of chert (as well as metal tools) were employed.
Eye shadow made from finely ground galena (dark gray) and malachite (green) was used by both Egyptian men and women. The grinding was done on cosmetic palettes carved mainly from metagraywacke. Egyptian temples and tombs were richly painted with bright primary colors made largely from ground stones: azurite (blue), gypsum and limestone (white), hematite ochre (red and orange), limonite ochre (yellow and brown), and malachite (green).
Grinding stones for grain have been used throughout Egyptian history, and generally were carved from the harder and less valuable ornamental stones, such as granite, granodiorite, and siliceous sandstone. During the Ptolemaic and Roman periods, large numbers of grinding stones made from imported vesicular basalt were popular.
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