IMILAC, CHILE
; PALLASITE
The following pieces were recovered on my 01/96 trip to the Atacama Desert site. I was very fortunate to find the nice larger samples offered here. Due to past and more recent collection activity, and mining operations that will soon encroach upon the site, future recoveries will be uncertain. Recent reports from a French team that went there in January 1997 indicate that it is now very difficult to find samples larger than 10 g.
Known since 1822, Imilac pallasites are sought by collectors for their unique forms. Each is different, and characterized by varying degrees of weathering, and hackly twisted metal. Some show signs of extreme disruption, possibly from a violent breakup of the meteoroid during the last phase of entry into the lower atmosphere.
There are two types, Type 1, and Type 2.
Type 1 is characterized in having fairly recognizable crystalline olivine inclusions. Most of the Type 1 examples have orange opaque olivines, but a few have been noted where the olivines are dark green and fairly clear. Usually, the clear crystals are found only in samples sawn from masses of 1 kg, or larger. Imilac specimens larger than 1 kg are extremely rare.
Type 2 is thought to show much more oxidation in that the olivine has been reduced to white clay like powder. But it is my opinion that this difference may not be due to weathering effects alone in that the iron matrix is very lightly oxidized in both types. The difference may instead be due to the explosive disruption of the meteoroid during its bolide phase, which produced the small fragments that are now found. Many specimens exhibit extreme distortion where the iron has been twisted and stretched. Metal bends, but olivine does not. Thus, when the iron matrix was distorted in the final explosive phase of the bolide, the olivine was shattered making it much more susceptible to weathering effects, hence the difference between "Type 1" and
"Type 2".
Prices are $7.00 per/gram
LARGER, COMPLETE IMILAC SPECIMENS
After searching the Imilac site for nearly a week, I found that specimens this size are now very scarce. They are all attractive "as found" examples. Due to the past collection activity specimens above 10 grams are now very hard to find.
1) A nice specimen with large cavities filled with olivine 24.8 g….…………………$SOLD
2) Elongated mass with traces of fusion crust and excellent olivine exposures 36.5g...$SOLD
3) A rare high metal form with deep cavities containing olivine 32 g………………….$224.00
4) Another rare high metal type with shallow cavities filled with olivine 37.6g………...$263.20
5) A very nicely shaped individual with trace of fusion crust and nice olivine 46.5 g….$325.50
6) A fine example with lots of metal projections, and olivine exposures…48.6 g……...$SOLD