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Whole Individuals |
Perhaps
the most basic type of specimen to collect is the whole individual. As
the name implies, this is simply a whole meteorite. One that has not
been cut or broken. Fusion crust may be present to varying degrees
(usually expressed as a percentage (e.g., 50%, 90%,
99%, 100%). Whole individuals may
range from a few grams (Holbrook comes to mind) to several scores of Kilograms
(Gibeon or Canyon Diablo). |
Slices |
A meteorite
slice is like taking a loaf of bread and slicing it into separate, flat-surfaced
pieces. It is literally a sawed slice from an individual meteorite.
However, the slice may be a complete slice,
in which case the perimeter of the slice is the actual exterior of the original
meteorite, or it may be a part slice, in which
case the slice contains one or more "straight cuts" from sawing.
Alternatively, the slice may be from completely within the interior
of the meteorite and thus the edge or perimeter of the slice will contain
no fusion crust. Slices are usually polished one one or both sides which is done to more readily reveal the internal nature, such as chondrules or unclusions, of the meteorite. Slices of iron meteorites, in addition to being polished, may also be etched with acid to reveal Widmanstatten patterns or Neuman line, if present. |
Fragments |
Fragments are
neither whole individuals nor slices. Imagine taking a whole individual
and beating it with an hammer. What do you get? Fragments!
Fusion crust may or may not be present. Fragments
are generally not polished but one usually finds chondrules that protrude
out from the background matrix. |
Endpieces |
Imagine the "loaf
of bread" example I used to describe a slice. True to the analogy,
an endpiece is one of the two ends. One "side" is the outer part of
the meteorite and the other sawed "side" is usually a polished face. As with
a whole individual, fusion crust may be present to varying degrees. |
Meteorite Micromounts |
Due
in part to the ever increasing cost of meteorites, many collectors
collect micromount specimens. Micromounts generally weigh up to
a gram or two and generally fit inside a 1 inch x 1 inch specimen case.
Slices are usually polished on one side (sometimes both) to reveal
the internal structure more clearly. Fusion crust may be present along
the outside edge or the piece may be an internal slice of the meteorite.
They are becoming popular among collectors because of various
reasons:
One can readily
see that a micromount may be a whole individual, a slice or part slice, a
fragment, or even an endpiece! |