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Given the dimensions of the book: "two feet broad by three feet in height, and over four inches thick", and being its pages made of "polished plates of electrum" (data from Forgotten Realms Campaign Set - DM's Sourcebook of the Realms, p. 92; TSR, 1987), what would be the weight of the book?

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1 Answer 1

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The density of electrum depends on the exact proportions of gold and silver, but ranges from around 12.5 g/cm³ to about 16.5 g/cm³ †.

Assuming the book is effectively a solid made of electrum 24 × 36 × 4 inches, its volume would be 3,456 cubic inches. This is equal to 56,634 cm³.

Given the density range above, this means it could weigh anything from 707 to 934 kg (1559 to 2059 lbs.). Based on our earlier assumption that the book is a solid, the actual weight would probably be a little less than that.

† The densities in the second source appears to have a minor magnitude error, in that 1,500 kg/m³ is impossibly light when electrum is composed of silver (~10,000 kg/m³) and gold (~20,000 kg/m³). If the digits are assumed to be correct, adjusting the magnitude to match that of silver and gold yields the sensible values of 15,000 kg/m³ and 16,500 kg/m³, which is 15g/cm³ and 16.5g/cm³.

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    \$\begingroup\$ There is a massive miscalculation here, as the density of Electrum varies between 12.5g/cm³ to 15g/cm³, which is 1250kg/m³ to 1500kg/m³. "," in the site you quoted is not a decimal point. \$\endgroup\$
    – MrLemon
    Commented May 8, 2014 at 17:02
  • \$\begingroup\$ Doh, my mistake. Thank you very much for the edit - I really should wear my glasses more often \$\endgroup\$
    – Wibbs
    Commented May 8, 2014 at 17:13
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    \$\begingroup\$ @MrLemon One of those sources is wrong by an order of magnitude: 15g/cm³ is 15,000 kg/m³, not 1,500, so they can't both be right. I just don't know which one. \$\endgroup\$ Commented May 8, 2014 at 17:26
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    \$\begingroup\$ Given that the densities of gold and silver are ~20g/cm³ and ~10g/cm³ respectively, I think ~15g/cm³ for electrum is the sane number. Which alters the calculation above considerably. \$\endgroup\$ Commented May 8, 2014 at 17:30
  • \$\begingroup\$ Wow, tough day for the math, I guess. 3,456 cubic inches is actually 56633 cubic cm, putting the weight more in the 680 kg to 900 kg range. \$\endgroup\$
    – Zimul8r
    Commented May 8, 2014 at 17:46

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