Wednesday, March 11, 2009

Agate--What is it?

Feature Article: What is Agate?

Agate is micro- to crypto-crystalline quartz. The term micro refers to the crystals being seen only with a microscope and crypto means hidden in reference to how small the crystal structure is. It can form through volcanic or sedimentary processes. Quartz is made up of silica so it tends to be hard and glassy. It is very abundant in nature and forms an endless variety of colors, patterns, and textures. These properties make it a perfect lapidary material. Agate is a common term for the mineral chalcedony.

Jasper is a term used to distinguish the darker colors of agate such as browns, reds, mustard, and dark green. Jasper is also used to describe agate that is coarse grained.

Terms like jasp-agate are used to describe agates that have both the properties of agate and jasper. While this term has endured, it is becoming archaic.

Utah has an abundance of agate and jasper. Most of the Utah material was formed as sedimentary rock but there are also volcanic agate in Utah, such as Wendover agate.

The formation of agate is extremely complex and not well understood by scientists. The variations and combinations are almost endless which makes it difficult to decipher how it forms. Notwithstanding, agate is common around the world and one of the most collected minerals. Because of its commonality, it is often taken for granted. The complexity of the bands and patterns mixed with the structures within the agate are dazzling to many. Utah agates are included in our Free Mineral Museum Display. Come in and take a look!

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