Pyrite, also called fools gold because of it's gold metalic hue is actually an iron sulfide, and when found where it has been exposed to the elements, is often rusty. Pyrite likes to crystalize in the form of a pefect cube, and most specimens, from the tiny ones found along the Arizona border in old mine tailings, to the large ones found Rio Tinto, Spain, are often obviously cubical in shape.
A quick word on crystalization. Minerals left to their own devices will want to form crystals based on their molecular make up. Crystals formed by any given mineral will almost always form in the same manner. As an example, almost all salt crystals will form cubes if left alone.
Many times crystals cannot form due to other minerals in the area interfering, this is what makes crystals in any form so collectable.
Pyrite is both beautiful, and inexpensive, making it a perfect place to start a rock collection. It comes in several spectacular forms, and can be purchased both in its natural matrix (its surrounding rock) and without.
Spain has some of the world's most spectacular pyrite cubes. These are available at the show at Tucson City Center. The cubes are sold both singly and in matrix, and those in matrix can be single or multiples.
A unique form of pyrite is called dollar pyrite, and is found in the coal mines of Sparta, Illinois. These unique specimens are available alone or in the black matrix, which can be very attractive. A small selection of these are available at the Ramada LTD show on the frontage road.
In Italy pyrite crystals sometimes are found in fossils, many beautiful, pyrite-laced cephalopod specimens are available at different locations throughout the gem and mineral show.
Some pyrite has a peculiar habit of losing its luster over time due to instability of a related mineral within the structure. Some pyrite specimens can, over time become very brittle, and in some cases will shatter of their own accord.
In the US, the most important pyrite specimens are found in Jerome, AZ and Leadville, CO, as well as the dollar specemins found in Sparta IL.
References: Simon and Schuster's Guide to Rocks and Minerals
Thank you for reading. Please join the conversation on Facebook. You can also subscribe to ensure that you miss no future articles in this series.
Comments