What is the density of granite stone?

According to 'Reade' ( http://www.reade.com/Particle_Briefings/spec_gra2.html ) the specific gravity and weight per cu/ft is

1. Slab Granite (2.69 - specific gravity / 168 lb per cu/ft)

2. Broken Granite (1.65 - specific gravity / 103 lb per cu/ft

This seemed a reasonable guide based on my experience. However, since stone that is typically referred to as granite is actually a composite of many types of rock material, including granite. Accuracy in determining weight would depend on accuracy in determining the composition of the rock.