Karen: I'm surprised no one else has offered an explanation as of yet. My guess, in part because I am potter, is that it has to do with the crystalline structure of the "stones". The reason I mention pottery is because many of my pots, when they come out of the very high temperature firing in my propane fired kiln (roughly 2350 F or cone 10 as the pyrometric cone number is called), have a wonderful and sustained ring to them when I rap my fingers on the rim of some pieces. Some can sustain that ring for half a minute or so. During the firing when the clay body is vitrifying and melting the various ingredients together into one another, a crystalline structure develops. Clay is basically composed of silica, alumina and various oxides such as potassium, sodium, lithium, calcium and a small handful of others that lower the melting temperature of the silica and alumina components. When they interact at the high temperature I fire to, that crystalline structure bonds all the ingredients into a very tight, hard material, extremely resistant to chemical attack. In general, the higher the firing temperature, the longer the ringing sound will last. As such, stoneware and porcelain pottery tends to have the better and longer lasting ringing sound than lower fired clay bodies such as earthenware.
Obviously not all stones (and I am assuming you are including stalactites and various other calcite formations in this category) are formed by heat reaction. Plenty of them, such as calcite formations, occur through crystalline growth without the application of heat. While those produced at higher temperatures may be stronger on a molecular level, that doesn't mean that they won't produce a ringing sound as a result of that crystalline growth. Plenty of stals have a long and sustained ring to them. There is also another factor involved in a prolonged ringing sound. In the case of my pots, the most pronounced ringing comes from bowl shapes. A platter may ring as well, but the longest and purest ringing tones come from bowl shapes. Mugs don't ring at all, nor do plates, but the molecular structure of the clay is essentially identical in all of them. The same could be said for stalactites. Short, stubby stals don't do much more than just clunk when they are rapped by a finger. Longer stals have a much greater resonance and it is likely due to the longer length vs girth of the formation. Soda straws don't ring, but a long stalactite certainly is much more likely to sustain a ring than virtually any other formation. This is certainly a very simplified version of why things ring and I hope that other more knowledgable people will respond as well. This is based mostly on empirical evidence from my own experience as a potter and a caver. Perhaps someone from Luray Caverns should answer this question as they are the ones with the "stalacpipe organ" which uses a keyboard driven hammer device attached to various "tuned" stalactites throughout the cave. It's pretty impressive.... Peter Jones On May 25, 2014, at 9:57 AM, Karen Perry wrote: > Does anyone know why some stones ring or have a musical quality? > Thanks, > Karen > _______________________________________________ > SWR mailing list > s...@caver.net > http://lists.caver.net/cgi-bin/mailman/listinfo/swr > _______________________________________________ > This list is provided free as a courtesy of CAVERNET
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