JEREMEJEVITE
“The locality name may sound a little strange BUT it
really IS just a mile marker in the middle of the desert,
and the jeremejevite-bearing pegmatite was stumbled upon
only by serendipity. Originally discovered in the early
1970’s and misidentified as aquamarine crystals, it was
only in the mid 1970’s that the blue crystals from Mile
72 were identified as jeremejevite (John Sampson White,
Smithsonian). Previous to that, in the late 1960's,
specimens of an unusual clear-to-straw yellowish elongated
mineral were found at this locality by John Saul (who
operates several African gem mines), although further
mining was not done at that time and he apparently kept
the specimens until recently when they were sold to
mineral dealer Cal Graeber. Because the newly mined
crystals are in fact identical to this FIRST discovery of
jeremejevite in form, color, and size, we purchased the
older ones and integrated those specimens with the
offering of this newly mined lot. With three claimants to
being the original discoverers, the true identity of the
first claimant is somewhat clouded. What is known is that
in 1975-1976 mineral dealer Sidney Pieters of Windhoek
pegged three lode claims on the location and initiated the
first large-scale recovery operation, an 18-month mining
effort.
In early 1998, mineral dealer Charles Locke Key (keyite,
ludlockite...) undertook an ill-fated mining effort using
the original miner, Peter Kittler, who discovered
"the pocket". This effort never got off the
ground and subsequently, Bryan Lees of The Collectors Edge
negotiated a lease agreement through his Namibian mining
company, Khan River Mining & Exploration (Pty) Ltd.
with Sidney Pieter’s daughter Shelly Mansfield, the
current legal claim holder. In January of 1999
sophisticated mechanized operations commenced at Mile 72
by Khan River.
Within the first week of operations Khan River Mining
& Exploration mined more rock then the previous
operation did through its entire 18 months. Unfortunately
in spite of the massive undertaking, (3500 metric tons
over 13 months) just ONE SINGLE POCKET of straw-colored
(these are not quite colorless!) jeremejevite was
discovered. This pocket produced under 200 single
crystals, only a very few at 2 cm in length or larger, and
a dozen or so specimens associated with feldspar crystals
(these matrix specimens mysteriously disappeared from the
claim, however, and appeared for sale at the Munich show
last year under mysterious circumstances). The largest
single crystal produced was 46mm in length (and is
available for sale on consignment from us, with Graeber
& Himes, at the Denver show for $3500). This pocket is
3m below MSL.
Operations were terminated in February-March of 2000
based on mounting expenses and lack of return. The
pegmatite has been largely mined out and it is reasonable
to assume that further production will be near-zero.
After a considerable amount of study a possible
mechanism for the paragenesis of the jeremejevite has
emerged. The Mile 72 locality is at the margin of a
continental rift generated +/- 540mybp when what is now
South America migrated from the supercontinent. During
this episode there developed a massive trench with
associated turbidite sequences. In conjunction with this
sedimentation, the Damara Orogeny was progressing which
resulted in high-grade metamorphism within the sediments
driven by the emplacement of the granitic Salem pluton.
This metamorphism produced a series of chemically
simplistic metamorphic pegmatites in the Mile 72 area.
These pegmatites are generally sill-like but lack a
source, indicating metamorphic rather than primary igneous
origins. The pegmatites are coarsely crystalline and
generally consists of feldspar, quartz and schorl with
minor apatites, lepidolite, & muscovite micas.
Approximately 100mybp the Cape Cross-volcanic event and
penecontemporaneous emplacement of the Uis tin tantalite
pegmatites occurred. These late stage Uis pegmatites
extend to Mile 72 and it is now presumed that the
jeremejevite was a remobilization crystal product
resulting from the intersection of an existing Damara age
metamorphic pegmatite, and one of the Cretaceous age Uis
pegmatites.
As a place to mine, Mile 72 is at once of unequaled
beauty and a complete back breaker. The weather is
impossible; equipment rusts at a pace unrivaled anywhere
in the world, and the hole itself is only fractionally
above the nearby sea level.”
(Article by Christopher L. Johnston - Omaruru,
Namibia)
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