This form is evident in other natural events. If the form could be visualized in three dimensions, it would look something like a soft pillow folded over on itself many times. If you can imagine moving three-dimensionally through a piece of Bruneau-pattern jasper, it is possible to go from the center of the rock to the outside and never cross one of the visual lines or edges. Unlike the concentric “shells,” one inside the other, that characterize the bands in a banded nodular agate, the edges that form the receding oval shapes in these jaspers are part of one continuous edge through the rock. It is important to point out that these shapes are not concentric like the bands in a nodular banded agate but are part of one continuous formation through the rock. Morrison Ranch jasper, or morrisonite, is found in Oregon on the east slope of the 2,000-foot-deep Owyhee River Canyon. This illusion of visual depth contributes significantly to the beauty of the generally opaque jasper material. Inside each resulting shape, the jasper changes gradually in hue and value, creating a visual sense of surface. The overlapping oval shapes are an illusion resulting from the repetition of the curved edge. This element gives the appearance of an oval shape behind the curved line that it crosses. An edge or line curves back on itself until it intersects with another line. The Bruneau jasper pattern is characterized by a series of overlapping oval shapes arranged in a circular format. The jaspers that share this pattern are considered by most to be the best of all jaspers. They also share a formational characteristic, a unique visual pattern not seen in agates. These jaspers are popular with lapidaries and collectors alike for their fine consistency, intricate patterns, and ease of workability. Major rock collections - both private and in museums - will often have fine examples of Bruneau jasper from Idaho or Morrison Ranch jasper from Oregon. The northwestern United States is rich in collectible jaspers. This example of Bruneau jasper shows the typical coloration and form associated with the jasper from Bruneau Canyon, Idaho.Įditor’s Note: This feature by Eugene Mueller, founder and co-owner of The Gem Shop in Cedarburg, Wisconsin, first appeared in Rock & Gem in March 2008.
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