Natural Science in Archaeology

11.2 Building Stone 259
Fig. 11.7 Acropolis, Athens, Greece: structures built from local marble and limestone
11.2.6 Slate/Schist/Quartzite
Slate is a microcrystalline metamorphic rock characterized by a highly developed
rock cleavage. The common colors of slate are black, gray, purplish, and greenish.
Composed of quartz and stable sheet silicates (such as muscovite mica), slate has a
high durability. Prehistoric tombs built of slate in the French Alps are still in good
condition after 2500 years. Slate is commonly used for roofing and paving tiles.
Schist is a metamorphic rock composed largely of quartz and muscovite, with a
pronounced foliation. It was used as building stone in ancient Greece. Large blocks
of schist were incorporated into the acropolis of the ancient city of Karthaia on
Keos Island (Kolati and Mendoti, in Waelkens et al. 1992). On Knossos, the “use
of irregular slabs of blue-green schist as the underlying material of painted stucco
is itself a marked characteristic of Minoan houses belonging to the transitional era
that marks the end of the Middle and the beginning of the late Minoan Age” (Evans
1964, Vol. II, Part II). Most schists fracture too easily along the planes of schistosity
(foliations) to be used in buildings or monuments.
In southwest India, during the eleventh to mid-fourteenth centuries CE, the
temples and sculptures were built from local talc or chlorite schists (Newman
1988). With these two soft minerals as major components of the rock, shaping was