An Article In Meteorite-Times Magazine
by Martin Horejsi of  Martin Horejsi's Meteorite and Tektite Books


Stone Orientation:
uevo Mercurio, Bensour & Millbillillie

Although meteorites need little more then their existence to instill awe, oriented individuals inspire an even greater admiration because of what they went through, or Maybe rather what they did not go through depending upon how you look at it.

Like the oriented Taza irons presented in The Accretion Desk of the previous edition of The Meteorite-Times, here are some oriented stones upon which to gaze.

The seemingly plentiful Bensour individuals, a recent fall, opened a cornucopia of oriented individuals to collectors. However with the additional collection value of orientation, there can sometimes be a little imaginative interpretation of what exactly constitutes orientation as captured in the form and skin of the meteorite. While I cannot begin to offer a comprehensive definition of orientation, I do feel confident that I’ll know it when I see it.

Below are pictures of orientated stone meteorites from the localities of Nuevo Mercurio, Bensour and Millbillillie. These three meteorite falls yielded many oriented pieces, but also many that are not. I apologize for the quality of some of the images. Given the small size of the some of the specimens, and the limitations of my digital camera, the depth-of-field is not as I had hoped

Nuevo Mercurio

Button, button, whose got the button? Mexico did in this case. The fall of Nuevo Mercurio in 1975, for some unknown reason, produced more than its share of oriented buttons with some shapes rivaling that of Australite tektites.

The leading face of the button is a classic tortoise shell covering the precious interstellar cargo contained within.

This fan shaped Neuvo Mercurio has a leading focus point that spreads out in a right triangle ending with a 180 degree trailing edge.

Like a hollowpoint bullet, this Neuvo Mercurio's leading edge developed a hole. It could be a burned-out chondrule or inclusion, or the result from the combination of hypersonic speed and the exact shape of the leading edge.


Like the wheeled Taza individuals, this Bensour seems to have rolled through the atmosphere all the way to earth.

I guess if there is a face on Mars, there can be a nose in the asteroid belt. This Bensour seems to have attempted a teardrop orientation, but gained a couple nostrils instead.

Tiny Bensours like this one acquired just a hint of a rollback rim. Their low mass probably prevented them from maintaining the airspeed necessary for a thick rim.

With the gentle contours of a sofa pillow, this Bensour seems to have floated to earth liberating unnecessary material, but maintaining almost imperceptible flowlines.

The beauty of turbulence is in the eye of the beholder. An ugly stepsister to smooth leading edges, trailing edges are equally impressive.

In what I can only guess is a case of animal mimicry, this Bensour has taken the form of a teardrop splash-form tektite. But it, like all tektites, it chose an evolutionary dead-end never surviving to reproduce because its shape is just too tasty for the hungry collector to ignore.

Six of one, a half-dozen of the other. Some bullets have concave trailing edges that helped to stabilize their flight, or conversely formed as a result of the unusually stable flight. This Bensour seems to have been working on its own trailing-edge concavity before it was so rudely interrupted by African dirt.

Imagine being a meteorite and watching the earth fall towards you. Now look carefully at the Bensour individual above. Imagine it an eye with the primary crust outlining the pupil, and the secondary crust in the center as the cornea.

The classic shape of this Bensour is somewhat amazing given it mass of just a tenth of a gram.


With the skin of an over-ripe avocado, this Millbillillie, except for the soil staining, has thick flow lines running like blood veins away from the leading edge. Note the circular area like an island or crater. I wonder that if given more hypersonic flight time, this feature would have developed into a hole like the hollow pointed Nuevo Mercurio pictured earlier.

This side view shows rimming so thick that it looks as if this individual has a healthy mop of hair on its head. The obvious features take little to imagine what went on to form the tar-like flow of eucritic material. This was one busy specimen during its fall.

A birds-eye view of the trailing edge of the same Millbillillie pictured above. The rimming formed such a deep pocket that the Australian outback soil had plenty of chance to pool in the pocket causing as rich a staining as I have ever seen.

This specimen is 99.9 percent perfect. It is a stair-stepping teardrop with amazingly well preserved flow lines within each of its steps. This individual of Millbillillie is a study of flowlines, orientation, and thumb printing all in itself. Look closely as the frozen wisps of calcium-rich material swirl around the hills and valleys of this spaceship from Vesta.

No, this is not the blunt end of the Apollo 11 capsule. Instead, this is the business-end of the teardrop Millbillillie pictured above. As is painfully obvious, the radiating flowlines extend away from a rather quiet concaved center; a sort of a calm in the middle of the storm.

And speaking of the Apollo 11 capsule.... This is a picture of the Wright Flyer reflected in the Plexiglas cover of the blunt end of the Apollo 11 capsule as displayed at the Smithsonian's Air and Space Museum. If you look closely, you can see the honeycomb pattern of the material that through its selfless sacrifice, ablated away the intense heat protecting Neil, Buzz and Michael on their return to earth.

The Accretion Desk welcomes all comments and feedback.