CompuServe Messages

>> I think you are saying that only quartz is well-polished in these gravels? I wonder what makes quartz (or any other mineral) more capable of a fine polish than another mineral. What is a polish anyway? I have a very vague memory it involves a melting of a very thin surface layer. << Ah, you bring up some interesting points. Among these stones, there are quartz pieces that are more and less polished. The granitic stone is not polished. The issue of surface melting (called the "silica gel effect") is interesting. Our student here, Sho, has demonstrated that it may not actually be what happens with silica. He has shown that polish is instead wear and erosion with no silica "melting" in at least some cases, and he's published his results. To my knolwedge, the "other side" of the issue has not yet responded, so the jury is still out, as it were. Cheers, GTL – Greg Laden, Written 15-Sep-1994 @ 10:20:42 Using: Windows NavCIS PRO 1.25