An oriented meteorite is typically cone shaped specimen covered with flow lines and display a roll-over rim called “lip”. This is the result of the passage of the meteorite through the Earth’s atmosphere, the heat generated by the high pressure in the front of the meteorite is enough to melt and ablate material away and roll-over onto the back side
If the meteorite travels through our atmosphere with a quite stable orientation, then the material will ablate from a particular point named the apex. The apex is more or less the middle of the face of the meteor from where the flow lines radiate in the front side of the meteorite.
For large oriented iron meteorite the regmaglyptes are elongated and radiate from the apex.
Typically the ablation results in a more or less flat “face” on the back side. Some oriented meteorites display on the back side a very thick fusion crust with bubble which is an accumulation of boiling material.
Sometimes described as bubbling, this thick crust on the back side is not necessary to define a meteorite as oriented but it’s only observed in well oriented meteorite.
Oriented Meteorites What about the word ORIENTED when describing a meteorite? Perfectly flight-oriented meteorite, meaning that the meteorite held a stable flight angle during entry into Earth's atmosphere, burning a curved face onto the stone. Price for perfectly oriented meteorite can be very high even for an common ordinary chondrite, in this case what makes meteorite so special is not the type, but the shape. In some case, oriented meteorites flow lines, emanating from a single point in all directions, some are shield-shaped with a very slight curve Oriented meteorites were studied by NASA when developing the manned space program to design the re-entry vehicle. Oriented meteorite give the best shape for maximum heat deflection and the way meteorites burned under the stress of entry showed NASA the best way and shape.