Fossilization: Top 4 Ways Fossils are Formed

Typically, when an animal, a plant or an organism dies, they decay; however, sometimes—with the right conditions—elements such as bodily tissues or traces are preserved resulting in the formation of fossils.

The process of how a fossil is formed is called fossilization and it occurs in a number of ways.

We’re taking a look at the most often cited ways of fossilization.


Permineralization is one of the most common methods of fossilization. When water coming from ground, lakes or ocean sets down into the tissue pores of the dead organism, it replaces the organic tissue.

Once minerals are deposited and crystallization happens in the porous cell walls, an exact cast of the organism is created. Woody plants, bones and teeth are most commonly preserved in this manner.


Impression fossils are usually found in clay or sand is often referred to as mold fossils. During the decay process, organisms leave behind their impression even though the organic material isn’t present.

Impression fossils don’t tell much about the biological markup of an organism directly but give clues to activity and traces of its life. There are a number of ways mold fossils are made however, all of the present a 2D imprint of the organism’s life.


Tracks, footprints, burrows, trail marks, droppings, boring and resting marks are just a few examples of how trace fossils are formed. Trace fossils reveal no information about the organic properties of the organism directly but provide extensive information about their functions of everyday life.


Have you ever seen a dinosaur skeleton in a museum? It probably got there due to fossilization by the cast method.

Organic material from a dead organism rots away, but in cast fossils, minerals start to deposit into the mold, creating a replacement of the body remains. This results in an exact 3D replica of the organism’s skeleton and bones. Cast fossils are found in sedimentary rocks either in frozen ice or ocean floor.

Fossilization Top 4 Ways Fossils are Formed 2

While many fossils are preserved for research purposes, many are used as alternative therapy. They have healing properties and support positive energy and stimulation of the mind.

Whether you’re a collector looking to buy fossils online and their replicas or an investor looking for minerals for healing purposes, get in touch with us at The Fossil Hotline on 508-715-5970 or online.

You can also check our online store and buy healing stones for jewelry with just a tap. Can’t find what you’re looking for? Send us an email on and we’ll get it for you!