Posted on 01/24/2007 10:19:19 AM PST by cogitator
First of all, another waterfall with basalt columnar jointing in Iceland (not a surprise, but another stop for the dream-trip itinerary):
Aldeyjarfoss
From childhood, I was always fascinated by the semi-precious gemstone tiger-eye. What is it?
"Tiger eye is quartz that contains oriented fibres of crocidolite that have been replaced by silica. Tiger eye is displaying chatoyancy (a vertical luminescent band like that of a cat's eye) . Tiger eye typically has lustrous alternating yellow or brown bands."
There's a word to impress your friends -- chatoyancy.
Nice examples:
Though yellow-brown-gold is the most common, tiger-eye also occurs in other hues:
** ping ** ping **
That's some serious geologic upthrust to create the vertical foliation.
Thanks for the ping! Love the waterfall. :o)
Ever heard of an "Apache teardrop?" I love that stone!
Actually, no (or if I have I've forgotten what it looks like/refers to). Enlighten me.
They are amber in color and when held to a light have a "teardrop" inside of them. They are absolutley beautiful.
Polished:
They're a variety of obsidian (volcanic glass), can be brown ("smoky obsidian").
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