How much does a 3.25 cubic foot granite stone weigh?

Question

I have a stone I lift that is 3.25 cubic feet - very smooth, very little air pockets - it is a beast, but I've found too many different ways to calculate the weight - anywhere from 312-lbs. to 536.25-lbs- does anyone know the correct answer?

Answer 1

The normally quoted density range for granite is from 165 lb. per cubic foot to 172 lb. per cubic foot. By simple calculation your stone must be between 536.25 lbs. and  559 lbs. assuming that it is solid all the way through.

Hope that helps a little.

Answer 2

Well it completely depends on the density. Not all granite is created equal. The mineral composition dictates its density.

When looking at large scale Earth processes, geologists tend to set the average density of the crust (which contains a lot of granitic material) at 2.8 to 2.9 g/cc or 2800 to 2900 kg/m^3.

Density = Mass/Volume

Assuming 2.8 g/cc and converting 3.25 cubic feet into cc (92029.7514 )

You can set up your equation as 2.8 = m/92029.7514

Solve for m. m = 257683.30392 g or 568.094441 pounds.

Again, this is assuming an average density of 2.8g/cc.