This lesson explores brass, one of the most significant copper alloys used in coinage since antiquity. Known as orichalcum by the Romans, brass played a crucial role in monetary systems and continues to appear in modern coinage.
Objectives
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Understand the composition and historical development of brass as a coinage alloy.
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Recognize the technological limitations on zinc content in antiquity versus later periods.
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Compare examples of Roman and modern brass coins.
Materials
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Sample Roman coins (dupondius of Antoninus Pius, sestertius of Commodus).
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Modern brass coins (Italian 5 cents, 1939; Yugoslav 10 para, 1976).
Lesson Plan
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Introduce brass as an alloy of copper and zinc, contrasting it with billon (copper + silver) and other alloys.
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Discuss the Roman concept of orichalcum and the typical zinc content (10–20%).
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Examine Roman brass coins, noting low zinc, small amounts of lead, and tin typical of the period.
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Contrast with modern brass coins, highlighting technological advances that allowed higher zinc content (30–40%).
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Conclude with a comparative discussion of Roman versus modern brass composition.
