[Jewelry making - Article 01342] - Re: [Orchid] Agatized dinosaur bones

[leonid surpin]

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>     Are there other stones that resemble the banding of agate in the
>     colours shown? 

    In general the process of fossilization is replacement of organic
    material with minerals. While in many cases the replacement mineral
    is quartz and therefore is the name agatized, it does not have to
    be. 

    Another class of fossilized material called marbleized. That is where
    replacement materials are carbonates like calcite, dolomite, and
    siderite. 

    Another group which can participate in the process are actinolites.
    These include barite, pyrite, and etc. 

    These are not exclusive, but simply a few examples. It all depends on
    mineral composition of the rock where process takes place. 

    In sedimentary deposits with high clay contents - replacement with
    pyrite will be encountered frequently. 

    In volcanic rocks - replacement with chalcedony will be found often. 

    So, all the different opinions on the subject are technically
    correct. 

Leonid Surpin.
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