Howardites
Howardites are named for Edward Howard, a renowned British chemist of
the 18th century and one of the pioneers of meteoritics - have a look at
our history of meteoritics. They are nearly as rare as diogenites, and
there are only about 50 members to this group if we exclude all probable
pairings.
Consisting primarily of eucritic and diogentic clasts and fragments,
howardites are polymict breccias. However, they also contain dark clasts
of carbonaceous chondritic matter, other xenolithic inclusions, and impact
melt clasts, indicating a regolith origin for the members of this group.
The howardites represent the surface of Vesta, a regolith breccia,
consisting of eucritic and diogenitic debris that was excavated by the
large impact that created the enormous crater near Vesta's south pole.
These fragments have been mixed with parts of the chondritic impactor, and
this mixture has been subsequently pulverized and metamorphosed by smaller
impacts and the solar wind to form an entirely new type of rock called
regolith. Similar regoliths cover the surface of the Moon, and as with the
howardites, these regolith breccias display high values for noble gases
that have been implanted into the rock by the solar wind. Our own planet
never formed any analogous rocks because it is protected by an atmosphere
and magnetic field, both protecting us from a continuous meteorite
bombardment and the destructive radiation of the solar wind.
Renowned members of the howardite group are the witnessed falls of
Bialystok from Poland, Kapoeta from Sudan, and Pavlovka from Russia.
Recently, several new howardite finds have been reported from the hot
deserts of Africa and Asia, e.g. Dar al Gani 779, one of the most
affordable howardites on the collectors market. We recently recovered
another new howardite from the deserts of Northwest Africa that will be
published as soon as a preliminary scientific analysis has been completed.
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Dar al Gani 779
Found : November 20, 1999, Libya
TKW : 18.8 kg
Howardite HED
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DAG 779-00
48.08 gr
A wonderfull endcut with crust !
Price
on request
SOLD
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Dag 779-01
40.45 gr
Very nice endcut with crust !
Price
on request
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DAG 779 - 02
5.10 gr
Triangular endcut, fresh and nice texture !
SOLD |
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DAG 779 - 03
3 gr
Very thin and nice slice with crust on the edge !
SOLD
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DAG 779 - 04
0.93 gr
Thick triangular slice !
SOLD |
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DAG 779 - 05
2.10 gr
Three slices of this fresh howardite !
170 $
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