Hi Teresa,

This is more difficult than it seems as the density of limestone depends on the form you want the limestone and the density of sand depends on how wet it is. The densities you can find at Mass, Density or Specific Gravity of Bulk Materials, a very nice site in the UK. The units are kilograms per cubic metre but Online Conversion gives you a tool to convert this to pounds per cubic yard.

For example the density of wet sand is given as 1922 Kg/cu m and Online conversion converts that to 3240 pounds/cu yard. Since there are 2000 pounds in a ton this is 3240/2000 = 1.620 tons/cu yard. But you asked for cubic yards per ton so this is

1/1.620 = 0.62 cu yards/ton.

Penny