Rock Type: Fossil, may be unaltered preservation or mineral preservation

Color: Varies.  Often grey or tan, but can be quite colorful depending on the mineral preservation
Gravity: Varies
Hardness: Varies,
Luminescence: Rare
Texture: Varies, often has vitreous layer on top with dull rock beneath
Transparency: Opaque

Where do fossils come from?

Fossils are found around the world, but large deposits are relatively rare.  Some of the best deposits are protected areas and the fossils remain in place.

Fossil Placeholder
Fossil
  • Petrified Wood often comes from Madagascar and the United States, with smaller amounts from Argentina, Australia, Canada, China, Egypt, Greece, Indonesia, Libya, Namibia, Pakistan, Saudi Arabia, and Thailand.
  • Agatized Coral is often from Indonesia and the United States.
  • Sand Dollar Fossils are mainly from Madagascar and the United States, with smaller deposits in France and Morocco.
  • There are many varieties of Shell Fossils, but Clam Shells most often come from Madagascar and the United States.
  • Turritella Agate is found exclusively in Wyoming, USA.
  • Vatican Stone is found exclusively in the UK.

What is a Fossil?

A fossil is the remnant or impression of an organism which lived in the past. Fossils come in many different forms and, depending on what is being preserved, the fossilization process can also be very different.  The four most common forms of fossils are unaltered preservation (Sand Dollar Fossil, Shell Fossil), mineral preservation (Agatized Coral, Petrified Wood, Turritella Agate), trace fossils (dinosaur footprints), and fossil impressions (Vatican Stone, leaf print).

Unaltered preservation typically involves marine or lake dwelling invertebrates, such as Coral, mollusks, sponges, etc.  The organism is fossilized in an unaltered state, a process aided by the fact that the animals’ skeleton is calcareous (calcium carbonate) and can remain virtually unchained when fossilized.  Calcium carbonite is also the main chemical components of Aragonite and Calcite.  Another example of unaltered preservation are insects or plant matter found in Amber.

Mineral preservation by contrast involves calcareous water seeping into the remains and gradually replacing the organic matter with minerals.  The minerals may be a grey or tan color, just like the surrounding sedimentary rock.  But when a stone is “agatized” it may be quite colorful.  In the case of Agatized Coral or Petrified Wood, the organic matter is replaced on a cellular level, preserving incredibly detailed patterns.

Petrified Wood

Petrified Wood, Arizona, USA

Fossil Shell

Mussel Shell Fossil

How are Fossils formed?

Fossils are remnants of organisms living in a past geological age. Most are preserved in fine-grained sedimentary rock such as limestone or shale.  Typically the soft parts of the organism decompose quickly and the hard parts, such as shells and bones, remain in place longer. Eventually the remains gradually turn into stone.  Fossilized Sand Dollar is the preserved remains of an ancient species of Sea Urchin.  The Shell Fossils sold on Moonrise Crystals are a type of ancient Clam.  Turritella Agates contain fossils of an ancient freshwater snail, Elimia tenera.

Petrified wood is the fossilized remains of ancient trees which flourished millions of years ago. Typically when a tree dies, it decomposes relatively quickly, leaving no trace behind. But occasionally, a tree may fall into a river or be swept away in a flood. When this happens there is a chance that the tree may be quickly covered with fine-grained sedimentary materials, such as clay or ash. As the wood decomposes, its outer structure is preserved and replaced by various silica minerals found in the sediment, including Chalcedony, and less frequently, Opal. These crystals create the rainbow of colors found in Petrified Wood. While any tree can potentially be fossilized, most Petrified Woods are a type of conifer tree, similar to modern Pine, Fir, and Redwood trees.  One notable exception is the Petrified Palm Wood found in Indonesia.

Agatized Coral begins in water but similarly involves a sudden covering of fine-grained sedimentary materials,  gradually replacing the organic material with minerals.  Any kind of Coral can potentially be fossilized.  The Agatized Corals from Indonesia are generally Brain Coral, Fern Coral, Hex Coral and Honeycomb Coral.  The Agatized Corals found in Florida are usually Great Star Coral.  Vatican Stone is another form of fossilized Coral, in this case Stag’s Head Coral

How are Fossils mined?

Most Fossils are mined from the primary deposit and typically in their original relationship with the host rock.   Fossils may be found on the surface of the earth or uncovered in any kind of mining environment. Except in the case of extremely valuable fossils, such as dinosaur bones, most fossils are mined as a secondary finds.  Agatized Coral is an exception to the rule, and is often found in geodes that wash up on the beach.

Vatican Stone is mined exclusively in Rogerley Mine, England. It was originally thought to be a type of Marble and was mined as a decorative stone for churches and the homes of the very wealthy. It is now correctly recognized as a Limestone, but is still used decoratively, in counters and floors in private residences.

Petrified Wood is found in many locations, often occurring as entire forest, sometimes entire trees are found.  Many of these Petrified Forests are protected and it is illegal to remove the fossils.

Real vs Fake Fossils

While fake fossils can be made, it is typically only worthwhile if the fossil is exceptionally valuable, such as a dinosaur.  Most common fossils such as Petrified Wood or marine animals are real.