Healdsburgites!

A new page May 13, 2015

"Sold" items current 8/04/17


In the Napa Valley wine country, near the town of Healdsburg, California, there is a sparse scatter of peculiar tektite-like black glass pebbles. Their skin is deeply corrosion-frosted and strongly ornamented with dimples and grooves. Their known distribution covers some 500 square kilometers, and reportedly, their age (2.823 +/- 0.006 million years) and chemical composition is quite uniform over this entire area.

Dr. Rolfe Erickson, Sonoma State University Emeritus geology professor, and his colleagues have studied these for many years. I remember a visit in the 1990s from the late Dr. Stephen Norwick, who was involved in this research. I provided a selection of known tektite specimens for comparitive studies (and Dr. Norwick gave me the only Healdsburgite specimen I have ever seen until now!). In a presentation to the American Geophysical Union in the fall of 2012, Erickson concluded "Their distinctive appearance, plus their identical ages and uniform chemistry, suggests these are tektites----". Newspapers and a wide variety of journals ran articles about the discovery of a new tektite strewnfield.

It is notoriously tough to solidly confirm whether an object is or isn't a tektite. Erickson's conclusion has thus far met with deafening silence, and, as far as I know, no other tektite authority counts Healdsburgites as a member of that peculiar community of meteorite-impact generated stones that we call tektites.

Healdsburgites have membership in what most of us consider the "pseudo-tektite" collective , which includes Arizona's Saffordites and South American Colombianites. There are others less well-known to me, but these three are so similar as to require a common origin. I do not mean to imply a single event (I am unaware of age dates for Saffordites or Colombianites, and that
would be big news if they all proved to be of the same age!), but rather it seems more likely that they are the product of a rather consistent geological process.

It is my belief, based on some pretty good lines of evidence, that these stones are the final skeletal remnants of volcanic obsidian that has corroded, hydrated, and devitrified until only little pebbles remain. (Glass is geologically unstable and inevitably does break down into assorted clays relatively quickly). Every obsidian flow is in some stage of devitrification. I think Colombianites, Saffordites, and now, Healdsburgites, are the last unaltered remnants from the hearts of obsidian boulders marching at the edge of geological extinction.

If this is so, new questions arise. A purely terrestrial origin would directly indicate that the dimpled skin, "U" grooves, and "navels" so widely characteristic of accepted true tektites can be produced by terrestrial processes alone. In contrast, the Indochinite "stretch" tektites argue that the dimpling formed in the first minutes of tektite history. Are we dealing with two different processes that can yield the same product?

Conversely, if these
are tektites, where are their respective source craters?

Either way, these curious glass pebbles play a pivotal role in the story they clench stubbornly to their breast.

Healdsburgites

Other than a few ugly bits offered on Ebay (that may not have even been true Healdsburgites!), I have never before seen these offered for sale. No dealers known to me have advertised Healdsburgite inventories. The table below may well represent the first and only offering of Healdsburgites to the general collecting community. These are superb specimens and I am thrilled to be able to offer them to you!

Be sure and have a look at our Colombianite and Saffordite pages for comparison. Their appearances are essentially identical, although Healdsburgites are much more opaque than the others. Thin specimens, and most weighing less than 4 grams do show translucence and gray coloration (but don't expect to facet Healdsburgites---).

39.0 gms $275Sold A monster patty. Some glassy chips and dings.
23.8 gms $240Sold oval biscuit about half as thick as it is wide. Some nice meandrine grooves
22.5 gms $230 Corrosion has elevated some internal layering into positive relief.
21.6 gms $300 Sold Deep and pronounced pits and grooves.
21.2 gms $220 Beautifully ornamented giant kidney bean
19.3 gms $200 Sub-cylindrical tall dome
16.1 gms $160 Roundish with a deep transverse "U" groove. A couple of glassy chips on the lip of the groove.
14.0 gms $145 Beautifully ornamented plano-convex patty.
13.0 gms $130 Through-going planar layer etched into negative relief by corrosion.
12.2 gms $135 Nice sub-cylindrical losenge shape
10.8 gms $120 Subtle layered aspect with a decent hint of a navel!
6.8 gms $90SOLD Symmetrical egg-shape with superb ornamentation.
6.7 gms $100 Sold Exceptionally high-quality thick lens-shape.
5.4(a) gms $100 Full of silky bubbles stretched like taffy, Mottled unique pale green-gray color.
5.4 (b) gms $75 SOLDVery nice complete, well-ornamented individual.
5.2 gms $75 180-degree segment of a navel!
5.1 (a) gms $75 A superbly grooved little losenge with a dragon face!
5.1 (b) gms $150 Sold Fairly gemmy interior. The most aesthetically pleasing specimen of the lot. This would make a gorgeous pendant.
3.8 gms $40
3.4 (a) gms $40Sold
3.4 (b) gms $40
3.3 gms $35
2.9 gms $35
2.4 gms $20
2.0 gms $13Sold
1.8(a) gms $14Sold
1.8 (b) gms $14 Sold
1.8 (c) gms $14
1.7 (a) gms $12
1.7 (b) gms $10 Sold
1.6 gms $10Sold
1.4 (a) gms $10
1.4 (b) gms $10Sold
1.2 gms $9Sold
1.1 gms $8Sold
0.9 (a) gms $7Sold
0.9 (b) gms $7Sold
0.8 gms $5Sold
1.9 gm total, set of three $8 Sold
1.2 gm total, set of three $6Sold
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