Follow by Email

Sunday, August 28, 2011

Calcite Replacement of Fossils

The term “fossil” is used for any trace of past life. Fossils are the actual remains of organisms, such as teeth, bones, shell, and leaves(body fossils). However, a fossil can also be result of their activity, such as burrows and foot prints (trace fossils), and organic compounds they produce by biochemical processes (e.g. waste products). Most fossils are created as a result of mineral replacement, such as in calcite replaced shells. Calcite, a carbonate mineral, which often forms  trigonal-rhombohedral crystals, can replace the original structure. The parts of the animals that didn't rot (usually the shell) were encased in the newly-formed sediment. After a time, the chemicals in the buried animals' bodies underwent a series of changes. As the shell slowly decayed, water infused with minerals seeped into the shell and replaced the chemicals in the shell with calcite. This process results in a heavy, rock-like copy of the original object - a calcite fossil.

All shells listed are available for purchase at Rock Hard Fossils LLC

Rare Calcite replaced sea snake eggs in coral              

Rare calcite replaced clam shell

Calcite replaced gastropod

Monday, August 15, 2011

Rock Hard, LLC

Watch for Fossils of the week on our upcoming blog.