THE CORUNDUMINIUM

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AMERICAS

Corundum has been found in many localities throughout the Americas. It is actually quite widespread, and literally hundreds of interesting if not economically important deposits exist in the Americas. Soon, we will have pages devoted to each country or region and what we know can be found there. To date, we have information about localities in Canada, Brazil, and the United States.

Here is what we plan initially for the United States. For the Northeast, we will have reports on New York, Massachusetts, Pennsylvania, and New Jersey. There is a southeastern distribution that runs from Virginia through North and South Carolina and Georgia into Alabama. The State of Montana contains the most important gem deposits, but other western sites of interest occur in Wyoming, Colorado, and California.. The "Original Site" contains remarks, but the plan is to reorganize, refine, and add further information as it becomes available and we have the time to do it. Clearly, the list of localities will continue to grow.

Below we have added some new information, not yet in final form or on the right page.

NEW WYOMING CORUNDUM DISCOVERY

Will Heierman, updated 9/9/07

I met a colleague in February, 2007, who recently discovered a new and significant corundum locality in Wyoming. The first specimen, found after years of searching, appears on the left. The clusters on the right are proof that the locality can produce produce superbly attractive mineral specimens!

The broken crystal on the left (donated to our collection by its finder) shows plainly a green alteration rind around a chatoyant or asteriated corundum core. The green stuff has been identified as a chromium-rich mica, probably fuchsite The spectacular cabochon on the near right is cut from similar material, and the green border is part of the rough's natural cross section (it is not intarsia). A different look is presented in the second cab on the far right. The annoying dust spots in the photos appear because I was chicken to take the glass lids off before photographing them.

The source localities are distributed over a large area more or less surrounding the Rattlesnake Mountains, southwest of Casper. I visited several in July, 2007, and took the pictures below.

Sorry, Amos! It's that one!

Rubies in situ

The rubies seem to have formed along contacts where pegmatites shot through ancient (precambrian) granitic intrusives. We dug in the soils below the exposed face in the second photo, and in about an hour had maybe 100 fine specimens. The matrix piece to the right, about 10" long, led to the discovery of another locality nearby. It is now in our display at Montana Tech in Butte.

"Owl Eyes"

Detail of owl eye

Our explorations indicated there are economic deposits here, but commercial levels of extraction will have both technical and bureaucratic problems that will need to be worked out. At present, there are about half a dozen of us who enjoy digging with hand tools and packing out the finds in buckets. If you are interested in obtaining some of this material, please contact me at wheierman@corunduminium.com. I do have some cabochon rough, some of which will probably star. The areas of concern are covered by unpatented placer and lode claims, so private digging requires permission. The owners prefer to remain anonymous for now; but iwhen that changes I shall provide a direct link here.

YOGO SAPPHIRES

Yogo Gulch, Montana was, in the early 20th Century, Americas premier gemstone locality, internationally regarded for its small but gemologically superb "cornflower blue" sapphires. Unfortunately, virtually all ventures on the property have shut down, leaving one "mom and pop" underground operation and a few "Sapphire Villagers" to extract stones from hand-dug dike material. See the Yogo Gulch page for more information.

CALIFORNIA CORUNDUMS

(Article under construction)

Though California seems to have little gem corundum, there are a few localities that produce collectible specimens. Most of these are in or near Riverside County.

One in particular (known as "Mount San Jacinto") produces outstanding grey elongated bipyramidal crystals which seem to have survived only as sections (parted perpendicular to the c-axis). The best of these have been cleaned and epoxied back together by the two brothers (Ken and Dana Gochenour) who found them. We have ten of them in the collection, and these appear below. One of them (the fifth, from left to right), known as "The Whale", is featured on our home page. Its main crystal is about 7/1/2 inches long, and the one to its right is 9 inches long. Sections found indicate that crystals up to 2 feet in length may have formed. Whether you find these opaque crystals worthless or priceless depends on your point of view.