rashley
Offline
• •
Upload & Sell: Off
|
Ioana, Yes, it is. Well, a section of one. For those curious...
Ammonite's shells, originally composed of aragonite, a carbonite mineral, which is unstable at standard temperature and pressure, and reverts to calcite over tens of millions of years. Actually, the shells inner surfaces had layers of nacre, or mother of pearl, an iridescent organic-inorganic composite (aragonite plates separated by proteins) secreted by the epithelial cells of some mollusk. During fossilization, the nacreous layer of some ammonites was chemically transformed into an iridescent material called ammolite, which is aragonite with varying mineral impurities that is considered to be an opal-like gemstone.
Edited on Jan 14, 2011 at 06:09 PM · View previous versions
|
