What Is A Geode Rock

Rocks which are completely filled with small compact crystal formations such as agate jasper or chalcedony are called nodules.

What is a geode rock.

Since geodes have hollow spaces in the middle they will weigh less than other rocks of the same size. A geode is a rock with a special surprise inside. Some geode rocks are the size of a pea others are the size of a soccer ball or even larger. From the outside a geode looks like an ordinary rock.

Geodes can also be embedded inside another rock layer such as limestone. Geo means earth and these amazing rocks. The crystals are formed by the filling of vesicles in volcanic and sub volcanic rocks by minerals deposited from hydrothermal. This celebration of geodes does not stop with iowa.

These rocks may range in size from a few centimeters to several meters in diameter and they come in many different shapes including spheres ovals oblong blobs and irregular masses. What you want to do is check the weight. Geodes are like the tootsie roll pop of the geology world because underneath the hard exterior lies a surprise center. Shells tree branches roots and other organic materials often decay away to leave a void for the formation of mineral materials.

In ohio a large geode called crystal cave is open for tours. Except for being kind of roundish there isn t much remarkable or interesting about them. Iowa a state known for its geode deposits has the geode as its state rock officially designated in 1967 and has a state park called geode state park. This can make geodes hard to precisely identify as whole rocks for the beginner.

If a rock like this is broken open however it will reveal a center that is filled with colorful crystals. The only difference between a geode and a nodule is that a geode has a hollow cavity and a nodule is solid. The term geode is derived from the greek word for earthlike and refers to a hollow rock with a crystal lined cavity. Geodes in sedimentary rocks are usually found in limestones dolomites and calcareous shale in these deposits a gas filled void can serve as the opening for geode formation.

The only true way to know if a rock is a geode is to crack or cut it open and find out if it contains a crystal core. A geode is a round rock which contains a hollow cavity lined with crystals.