Gujba, Witnessed Fall Bencubbinite, Rare Iron Nodule, .233g

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On the evening of April 03, 1984, a brilliant fireball lit up the night sky over a series of villages in the Yobe region of Nigeria. Local residents reported hearing a loud explosion and were later able to find a single large meteorite that weighed at least 200 pounds. Superstitious villagers and treasure-seekers used hammers and chisels to break the meteorite into many pieces, which were removed and taken away. Western dealers managed to acquire a portion of the mass and have it analyzed by scientists.

Scientists were amazed to find a rare Bencubbin-like type, of which fewer than ten are known. Bencubbinites are a bizarre and wonderful type of carbonaceous chondrite that is unlike anything else known to meteorite science. Up until Gujba, no other Bencubbinite had been a witnessed fall. Scientists had to settle for a limited amount of study material from specimens that were decades old. Now they had the first fresh example of the type. A flurry of research has been done in the years since this recovery that has shed new light on the formation of this curious type of meteorite that doesn’t neatly fit into the carbonaceous chondrite family, but has carbonaceous affinities that preclude it from being an ungrouped type.

Gujba, like all Bencubbinites, is composed of a silicate-rich stony matrix that is populated by unusual metallic spheres. They are like big chondrules composed entirely of solid meteoritic iron. It wouldn’t be a stretch to compare them to ball bearings. When a Gujba mass is sliced with a saw, these metallic nodules are revealed in cross-section (like chondrules in a ordinary chondrite). As a result, this meteorite has a unique and aesthetically-pleasing appearance that appeals to collectors.

As one might expect, when Bencubbinites are cut, these metal nodules can be jarred loose and fall out of the host matrix during the cutting process. I have long sought after some of these loose nodules, but they have been impossible to find. Not many dealers have Bencubbinite material and even fewer slice it up. Since these nodules rarely fall out, it takes a lot of slicing and polishing to free up any reasonable number of them. After many years of inquiries to dealers around the world, I finally found some.

I was tempted to clean these up to remove the stony material still clinging to the surface of the specimens. I didn’t want to risk contaminating them with a cleaner and rendering them useless for research purposes. I suppose one could use a tiny Dremel brush head and clean them up that way, but it would require some kind of clamp to hold the nodule and a steady hand. I think these would look amazing cleaned up and showing shiny reflective metal. If you decide to clean one up, let me know the results.

If you like loose chondrules, you are going to love these little cosmic ball bearings. The lot I acquired are all solid iron – no silicate nodules. I checked them all with a magnet – they strongly leap to a magnet and are very dense and heavy for their small size. They weigh much more than a similarly-sized stony chondrule would weigh.

This is the first time in my decade and a half of collecting that I have gotten my hands on these. I have only seen one other dealer offer a single nodule for sale in the past. It wasn’t easy to get these and probably won’t be easy to get any more. I acquired fifteen of these nodules. I put two into my personal collection and will be offering the remainder to collectors.

The specimen being offered here weighs .23g (.233mg).

Refer to the photo. The black centimeter cube is shown for scale and is not included. You are purchasing the nodule shown. Your purchase will include a labeled gemjar for safe storage.

From the Meteoritical Bulletin entry on Gujba :

Yobe, Nigeria
Fell 1984 April 3, 18:30 local time
Bencubbin-like meteorite

A conical meteorite fell in a corn field near the village of Bogga Dingare after a bright fireball was witnessed moving west to east and an explosion was heard. The local people hammered the meteorite into many pieces, and most of the material was dispersed. The original mass is unknown, although secondhand reports indicate that it had a volume of ~20 000 cm3, and thus a mass of ~100 kg. Material that almost certainly came from this fall has been sold in the last few years elsewhere in Nigeria, with claims that the specimens were new finds. A preliminary description of the meteorite appears in Islam and Ostaficzuk (1988). Description (L. Karwowski, USil, based on the original mass): contains metal nodules, 1.5–8 mm in diameter, and silicate nodules 1–15 mm in diameter with fan-like aggregates of pyroxene; 60% of nodules are metal. Description and classification (A. Rubin and G. Kallemeyn, UCLA, based on a 282 g fragment purchased in 2000 near the village of Gidan Wire in Kaduna state): consists of large metal nodules containing variable amounts of troilite, and cryptocrystalline silicate spheroids; silicates include pyroxene (Fs1–2Wo1–3) and rare olivine (Fa3); siderophile abundance pattern in metal is similar to that of Bencubbin; shock stage, S2; weathering grade, W0. Oxygen isotopes (R. Clayton, UChi): light-colored silicates, δ17O = -2.19·, δ18O = +0.53·; dark-colored silicates, δ17O = -1.78·, δ18O = +0.98·. Specimens: 12.2 kg, mostly disintegrated, UMaid; 815 g, MZP; type specimen, 64 g, UCLA; remainder of 282 g mass, Twelker.