Just found some really nice grey slate with a nice silver metallic fleck to it - will look great under our soon to be delivered ivory enamel F500 Oslo. It's not cheap at $7 per sq ft, but I don't particularly mind the cost as long as I don't have to replace it in two years. It will be on top of concrete board and ceramic board. Any comments from people with slate hearths - wear, spalling, cracks, etc. One caveat - the stove will be moved once a year for cleaning (don't ask), but I do intend to build a little wheeled cart that I can slide under the stove, lift the stove on jacks and move away from the stove pipes... Thanks.