Page 265 - Copper and Bronze in Art: Corrosion, Colorants, Getty Museum Conservation, By David Scott

color, which can be altered by treatment with acids or ammonia, varies from greenish blue to
apple green. The mineral is generally massive, but in certain localities crystalline turquoise may
occasionally be found (Braithwaite 98i; Schaller 1912). More commonly, it is found as a surface
i
mineral in small compact lumps, often associated with azurite or malachite, and sometimes as
outcrops in veins of lead minerals. Turquoise is frequently found as a pseudomorph after ortho-
clase, apatite, bone, and teeth (Palache, Berman, and Frondel 1951).

The history of turquoise Turquoise appears at an early date in Iraq and was used for
beads, examples of which were excavated from the sixth-
millennium B.C.E. site of Tepe Zagheh on the Iranian plateau and from the early site of Ali
Kosh, Iran. The use of turquoise for beads, often in association with lapis lazuli, continued in
this area throughout the prehistoric period. Afterward, the stone became rare in Mesopotamia,
either because substitutes were available, as Pliny suggests in his observations quoted earlier, or
because the supply of raw material became disrupted.
Areas where turquoise may have been mined include Iran; the Sinai Peninsula; the inner
Kizil Kumy, southeast of the Aral Sea; and Afghanistan. Pliny writes in his Natural History
of one source:

A far purer and finer stone is found in Carmania. In both localities, however, callaina
[turquoise] occurs amidst inaccessible icy crags . . thus tribes accustomed to riding on
.
horseback and too lazy to use their feet find it irksome to climb in search of stones. 7
This region of Carmania, the area of Kerman province in Iran, is the same region noted by
Marco Polo in the thirteenth century as "a source of the precious stones that we call turquoise." 8
I TURQUOISE ARTIFACTS FROM THE EASTERN HEMISPHERE
Turquoise is not a suitable stone for carving into seals, but there are a few finds of unusual
type; for example, a small turquoise amulet in the form of a calf's head, now in the collections
of the Musée du Louvre, which is inscribed for King Kadashman-Turgu of Babylon (ca. 1298-
1297 B.C.E.).
Turquoise often occurs in jewelry of the Seleucid to Parthian periods (300 B.C.E.-100 C.E.)
in Afghanistan (Moorey 1994). Numerous other locations where turquoise was found and
worked are listed by Palache, Berman, and Frondel (1951). Turquoise has been used extensively
for small beads and jewelry in both the Old and New Worlds 9 from prehistory to the present
day, although there are many blue-green stones or beads described as turquoise that may
actually be chrysocolla or another mineral. Vallat (i983) found a fragmentary text about King
Darius I of Sumeria from excavations at Susa in southwestern Iran, which revealed that the
Sumerians had a specific word for turquoise, ashgiku, in the Akkadian language.

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