1 ton of gravel is a pile of stone weighing 2,000 lb (907 kg). It takes up 141 gal (534 L) of space, which is about the size of a refrigerator.

Volume
141 gallons
141 gal (534 L)
about the size of a refrigerator
Gravel typically ranges 1.6–1.9 g/mL depending on how it's packed. A firmly packed scoop weighs more.