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| Obsidian |
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From the Latin obsidianus lapis, a natural
glass of volcanic origin of varied chemical composition,
usually shiny black in color with metallic reflections.
One of the materials used the most by ancient man for
the elaboration of weapons and utensils.
Term used to specify glass of volcanic origin, usually
of rhyolitic composition, formed by the rapid cooling
of molten igneous rock where its constituent ions did
not have the necessary conditions to group in defined
interatomic structures and crystallize. Hardness of 5.5
according to Mohs scale. |
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| Opal
Or Opalescent Glass |
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One of the procedures for the
making of this glass is by adding bone powder to the mix.
Opal glass was highly valued in Bohemia and France where
opal crystal and glass were made. Now a days it is known
as “opalescent.” Said of any glass into which
a material has been introduced at the raw materials stage
(usually fluorine or phosphorus) |
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