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EUCLASIO.
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precision in any determined class. The following table of three analyses made by Barbot of the eu-clasio shows how differently it may be composed in various crystals :
The colour of euclasio varies from green to blue in multiplied gradations of tints, and on this account it might be placed amongst beryls, were it not for the glucine it contains, which assimilates it more to the emerald. It becomes electrical by friction and in­creases its cleavages.
It was from the beginning considered a green topaz, but it is distinguished from it by being more fragile and having less specific weight, not reaching to 2-9.
It has double refraction, and under the action of the blow-pipe becomes opaque, and changes into a kind of blue enamel.