Something unusual about the Liberty Bell is that its composition is uncertain. In fact, two different analyses of the metallic composition of the Liberty Bell came back with considerably different results, as far as percentages. The Franklin Institute took samples in 1960, while the Winterthur Museum and the DuPont Company did their own analysis in 1975.
In general, though, the bell is roughly 70% copper and 25% tin. Other metals, in amounts between trace amounts and five percent, depending on which analysis you read, include nickel, gold, arsenic, antimony, silver, iron, zinc and lead.
The original weight of the bell was 2,080 pounds -- 44.5 of that was just the bell's clapper. The bell measures 12 feet around at the lip (the bottom), and 7-1/2 feet around at the crown.
The most famous measurement on the Liberty Bell may be the length of the crack. The first crack, that was widened as part of an effort to stabilize the bell, measures 2'4" while the hairline crack that later formed, and sent the Liberty Bell into retirement, measures 2' 1/2".