Heatho said:
Plenty of Billy's in the New England gemfields mate. Sure I've seen them at Sapphire Bend as well.
Oh ok - a couple of people have told me they don't get them there.
Are we talking about the same thing? What we refer to as "billy boulders" up here are a very specific rock - they are hard and composed of quartzite and more often than not posses an unusual shape and smooth, almost polished surface appearance that has previously been described as "water-worn" but having seen countless numbers of them, I have to agree with Jim Elliot's argument that they are in fact
heat-glazed. At least the surface looks that way.
They vary in size from small things the size of a fist, through to basketball size, through drum size and occasionally as big as a car bonnet or bigger. I had a 44-gallon drum sized one in my hole on our ill-fated claim at Reward, was a real pain to get out of the hole!
They are often taken as a sign of the potential of sapphire-bearing wash as they often seem to accompany the stones, many believe this is a sign that they were ejected from the volcanic vents along with the sapphires, black spinel etc.
They actually make a handy bush building material and there are plenty of miners huts and houses on the field that use them as such. The Rubyvale gem gallery was originally built from them.