ODDS’N’SODS — Diamonds in the Appalachians

The occurrence of diamonds in the eastern U.S. has been well documented since 1843, and possibly even earlier. The authenticated diamonds range in size from 0.25 carats to the Punch Jones diamond, which weighed 34.46 carats.

There are various, less well documented reports of larger diamonds from the region, ranging from 40 to more than 100 carats. These reports may be subject to some doubt, but, because of the well authenticated existence of stones in the 20-to-30-carat range, they cannot be completely dismissed. Dozens of diamonds have been reported. Several of these stones have interesting histories. The Dewey diamond, for example, which was found in 1854 at Manchester, Va., weighed 23.75 carats. It was the largest well authenticated diamond found in the U.S. for many years, and was subsequently purchased by the then-heavyweight boxing champion and cut into a gem weighing 111116 carats, which he had set in a ring.

The Punch Jones diamond was found at Peterstown, W.Va., in 1928 by William “Punch” Jones while he was paying horseshoes in a vacant lot. It was kept by the finder for several years prior to authentication and description by Roy Holden. This stone was in the Smithsonian Institution collection for many years, on loan from the owner; it was later returned at the owner’s request. Diamonds have been reported from New York, Maryland, Virginia, West Virginia, North and South Carolina, Georgia, Alabama, Kentucky and Tennessee. The origin of these diamonds is subject to debate.

One explanation is that they were transported by glaciers. While certainly possible in New York state, this hypothesis is doubtful with regard to most of the other areas, as they have not been subject to continental glaciation during the past hundred million years or so.

In the case of the diamond found in 1913 on the Gillespie farm near Pounding Mill, Va., it was suggested that it may have been deposited by migrating birds from South America. This hypothesis, while interesting, is subject to doubt.

Several writers have suggested that the stones may have been transported from distant, unknown, original-source areas by streams. While this idea certainly seems possible, it leaves unanswered the question of the location of the original source area or areas.

One explanation, offered for a specific example, is transportation from a distant known-source area by human agency (that is to say, salted with South African diamonds). This explanation is probably correct for the particular case that involved attempts to sell properties and raise money for diamond mining in an area in which diamonds were known to exist. However, it does not account for the large majority of the known diamonds found.

An explanation much favored by writers and pioneer geologists in the 1800s was that the diamonds had weathered from Itacolumite (micaceous sandstone) formations based on the known examples in Brazil at the time. The Brazilian occurrences have since been identified as paleoplacers, not in situ source rocks. This hypothesis is subject to considerable doubt as the diamonds do not seem to be preferentially associated with any sedimentary formations. While the migrating bird hypothesis has certain attractive features (especially insofar as the birds would provide a method of transport from areas in which diamonds are known to occur), we still have difficulty in accepting it. Several of the other proposed mechanisms appear to have some partial validity.

In view of the significant size and quality of individual stones and the wide-spread occurrence of the Appalachian diamonds, exploration appears merited. The Appalachians and adjacent areas could well offer high-potential diamond prospects.

— From a previously published article. James Bond is a consultant in West Virginia, and W.D. Hausel is with the Wyoming Geological Survey.