Greg 'Giggles' Fraser (can we call you Giggles?) writes: > 1. I believe I read somewhere that transparent but colored objects appear to > be the color they are because photons of light strike their atoms and excite > the electrons which then emit energy as they drop back down to their natural > state and the frequency of this energy dictates the color that we see. (more > or less. I know the human eye and mind as well as the atmospher do influence > our perception.) Did I understand this correctly? that's pretty much the way I understand it, but there is also the state of interference to confuse the issue, such as when looking at gold (thin or in solution) - yellow by reflected light and blue by transmitted from memory ... I don't see much of this stuff anymore ;-) you see the same with dichroic filters . > I believe I just solved question 2 myself. It took so long to type out and > to word clearly that I figured it out just by concentrating on it. Marvelous! >I have > wondered for a long time why when crystals form (say in a geode) they form a > somewhat random mass (like snow) which are tny crystals >out of which shafts grow. I didn't know how > the crystal knew to change their growth pattern from the snow shape to shaft > shape. What I think happens is the crystals form all around the interior of > the geode simultaneously and grow until they hit another crystal. This forms > the random snow but some of the crystals do not hit others and therefore > continue to grow in the shaft shape. This might well be a question for a mineralogy group but I may be wrong. I did some electromicroscophy pics once of some teeny weeny crystals and they looked just like a big crystal only smaller - I think the arrangement of the bonds pretty much determines how each molecule of a crystal is laid down, they just slot into one another in a neat patern - asbestos is an odd one though and I could never get my head around how it does what it does and why it arranges to form a little tubule. back to the geodes - I guess as each dissolved molecule seeps through the porous rock into the pocket, the first seed crystal is laid down and it procedes from there - each following disolved salt will be attracted to the crystal and the bonding process continues. I guess I really should watch a crystal grow one day.. > Well anyway, what about the question 1? Ever heard of that theory before? no. sounds like witchcraft.. karl
