Binghamite / Silkstone

A chatoyant variety of Chalcedony containing fibers of goethite and/or hematite, Binghamite / Silkstone is found only in the Cuyuna iron range (near Crosby) in Crow Wing County, Minnesota. Mining in the area uncovered deposits of the stone, but since mining operations were discontinued in the area many years ago the stone has become fairly rare and is sought after by lapidarists and gem collectors. The best binghamite compares with top pietersite for color and chatoyancy and is often referred to as “the American Pietersite”. When the stone’s pattern is arranged in level lines it is called silkstone. Binghamite and/or Silkstone is all but extinct nowadays, and even the old mine dumps and tailings have been thoroughly depleted long ago.

Please enlarge and view the photographs for more detailed views. Shown wet to simulate polish. As with all natural rock, there may be fractures or pits to seal or work around. Each slab has the approximate dimensions listed. I use the longest and widest point and the thinnest, it’s not averaged.

If you like this material you will also like charoite, bronzite, and tiger’s eye.

We have worked hard with the lighting and the settings on the camera so that the colors are very accurate. Individual settings may affect color viewing on various devices and I cannot predict what your device will do, but on my computer, they’re dead on for color. I appreciate your business!

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