have argued that the Mesopotamians traded “invisible exports” (sensuCrawford 1973 )
such as textiles or oils in exchange for metals, stones, and timber from the Gulf and
South Asia. Indeed, pre-Sargonic texts from Lagash record Mesopotamian grain,
aromatics, flour, wool, and silver being exchanged for copper and tin from Dilmun
(Foster 1977 ). Of these Mesopotamian products, only the silver would be obvious in
the archaeological record today. Of course, silver did not originate in ore-less
Mesopotamia just as copper and tin did not originate in ore-less Dilmun, so even if
silver were found at Harappan sites, the material itself could tell us little about such
trade. More puzzling is the suggestion of pre-Akkadian tin coming from Dilmun, since
tin–bronze does not become common anywhere in Iran (Thornton 2009 ), the Gulf
(Weeks 1999 , 2003 ), or the greater Indus Valley (Kenoyer and Miller 1999 ) until after
the Sargonic period. Tin would seem to be an “invisible export” of a different variety.
The idea of “invisible exports” such as grains, textiles, and oils may hold water when
speaking of Mesopotamian trade with Dilmun or even the west coast of Magan (i.e.,
the Emirati coast) (Edens 1992 : 127 ), but it is hard to imagine huge shipments of grain
or textiles being needed in the lush Indus Valley by the industrious Meluhhans.
Uerpmann and Uerpmann ( 2008 ) have recently proposed the export of Mesopotamian
sheep/goats to Magan and perhaps to the Indus Valley in the later third millennium
BC, although they await further studies to test that hypothesis. Nevertheless, if
–– Christopher P. Thornton ––Figure 31.2A hoard of copper bun ingots discovered at the late Umm an-Nar site of Maysar in
northern Oman (Weisgerber 1981 : Abb. 39 ; courtesy of Andreas Hauptmann). Similar ingots have
been found at third millennium sites from Syria to the Indus Valley, and may have come from
“Magan” (see Weeks 2003 , 2007 )