Handyman and Dougwalkabout,

See my post right above yours. The stones we used around our fire ring were fractious basalt that had been sitting under 3 to 6" inches of snow for only a couple weeks; snow that had been subject to considerably thaw which would've kept the rocks nice and moist.

As a general rule, if you must use rocks that are under the snow, try and select solid igneous types that are beneath well drained soil. Even better, find ones that are beneath heavy litter (leaves, debtritous), which can act as a good moisture barrier.