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Re: Smiley Faces!



On Wed, 23 Sep 1998 10:00:44 -0400 Chuck Britton said:

So now we know that Quartz-Halogen bulbs are CRYSTALLINE!!!!


or maybe that they don't contain quartz?
We had a good discussion about the halogen part a while back and I think we got
that part straight. Anybody know where the quartz part of the name comes from
Is it because the hotter bulbs require a higher melting glass and somebody
decided to call it quartz?

Quartz is a mineral name, and like all minerals has a definite crystaline
structure. Melt the quartz and then cool it quickly so there is no long
range crystaline structue and you have glass. This is the definition of the
term glass and it is how glass is made. You don't have quartz any more.
I guess I should be clear that you don't have to start with quartz to get
glass, it is the lack of order that makes it a glass. Maybe people are using
the term quartz for SiO2, but SiO2 is silica. A quartz rich rock has quartz
crystals in it. A silica rich rock has a high % of SiO2, but need not contain
quartz. You guys get all bent out of shape when the terminology of Physics is
not used correctly, so you should be happy to learn correct usage of
terminology from other sciences.