2-3/4" Dryhead Agate

2-3/4" Dryhead Agate

Availability: Out of stock

Quick Overview

The development of this nodule's banding is unique.

Measurements: ~ 2-3/4" in diameter
Location: Montana, U.S.A.

More Information:

Agate is a form of Chalcedony pronounced Kay-sed-ony), made up of 90% quartz and 10% morganite. It is composed of microscopically fine fibrous crystals and it normally shows color banding, stripes, whirls, bull's eye and other random patterns due to impurities in the quartz. Igneous rock is formed by lava and volcanic activity. This activity can form pockets / bubbles in the rock, similarly to Swiss cheese. When these pockets are formed in an area close to water, the water which is filled with minerals, (primarily quartz), is forced into the pockets, forming a layer of gel which eventually eats away the igneous rock. Layer upon layer of this gel is created until the void is filled and the water dries out, allowing for complete crystallization. These pockets can be broken up over time, then washed into the waterways where it can be naturally smoothed and polished. Sometimes a pocket it will remain intact and the void will not fill completely, as in the case of an Agate Geode.

Dryhead Agate, from the area of Montana between the Big Horn River and the Pryor and Big Horn Mountain ranges, is one of the most exquisite agates found in the United States. Most of the Dryhead seen on the market is material that was collected between the 1950's and 1980's. It is famous for demonstrating colors of red, yellow, pink, and orange.