Question: Is agglomerate marble tile heat proof enough to use as a decorative surround on a direct-vent gas fireplace? (Apparently solid marble is O.K. but no one seems to be sure about the agglomerate or fused marble material's heat resistance.) Answer: In cases that I have seen, this type of material comes out OK. However, there could be many materials and processes used to make it, and there are also differences in the front temperature of various gas fireplaces. In fact, some gas fireplaces allow wood or sheetrock to be brought right up to the unit...with just a 1/8 inch gap that should be caulked. If this is your type of fireplace, then it is almost surely OK. If yours specifies much more clearance around it, it may be an indication of higher temperatures in that region. In this case, it would be nice to see if the material (marble) had a published flame rating. The manufacturer of the fireplace may also be able to help.