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**Petrology:** Paragneiss is composed of feldspar, quartz and biotite associated with minor silimanite, garnet, cordierite or muscovite. Greenish calc-silicate gneiss contains pyroxene, plagioclase, quartz and garnet.
**Genesis:** Paragneisses were formed during the process of regional metamophism of clay-sandy marine sediments under relatively high pressure and temperature conditions. Calc-silicate gneiss is produced by contact metamorphism of carbonate rocks (limestone), which contained clastic quartz (marl/marlstone) or a clayey admixture.
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mineral halite texture color ornamental stone semi-precious gemstone