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Figure 3. Map of the Langesundford area. The
main cities are linked by highways, but the swarm
of islands in the fjord are accessible only by boat.
The three islands of main interest are Lovoya, the
discovery site of thorite by vicar Esmark; Ldven,
the historic source of mosandrite, a source of lan-
thanum; and Sylteroya, the location of vicar
Esmark's church. About 15 kilometers north.is
Skien (not shown), the home of the playwright
Henrik Ibsen.
our host for our visit to Norway and led us on a
retracing of Esmark's discovery. There is no rou-
tine ferry service to Lovoya, and Alf took us in
his outboard for a tour of the islands in the
fjord. He headed from his home in Stathelle
(Figure 8), through the Brevik harbor, and then
straight to Loveya (Figure 4)."Today we do not
know exactly where Esmark discovered the
mineral, Alf was telling us as we cruised
through Brevik harbor." Esmark mentioned in a
letter to Berzelius that when he returned after
the winter thaw, he assumed that ice had
weathered out some of the minerals. That
means it was close to the shore."Alf told us that
he had scoured the whole of Lovya and had
Figure 4. The exact location of the "thorite hole,"where vicar Esmark discovered the original thorium
mineral, is not known. This is a possible location (N 59' 03.45, E 09' 44.08) identified by Alf Olav Larsen,
the foremost mineralogist of the Langesundford area.
Figure 5. This 20-cm specimen is from the
Langesundfjord area. The dark thorite (ThSiO4 is
in a matrix of syenite pegmatite, an alkali feldspar
rock mixed with hornblende and other minerals
but lacking quartz.
found only a few candidates, close to the shore
where the ice would have formed. In the old
days the locality was called the 'thorite hole'
(Figure 9)."As Alf maneuvered the boat to dock
at a mineralized headland, an eider hen scurried
away with her brood.
Unfortunately no more thorite can be found:
"After Auer von Welsbach invented his incade-
scent mantle which uses the refractory thorium
oxide, there was a 'gold rush' in 1895-1896,
which essentially cleaned out the thorite in the
Langesundfjord islands." (note 4).
In his boat, Alf toured us across the open
water of the fjord to gain a larger view. The
scenery in Langesundfjord displayed an ancient
Figure 6. Brevik kirke (N 59" 03.16, E 09 42.15)
on Sylteroya, an island linked to the mainland
part of Brevik by a bridge. This stone church
replaces two earlier wooden churches, demolished
in 1879 and burnt down in 1960, respectively.
panorama of geological variety. From the mid-
dle of the fjord, we scanned the horizon and
viewed almost a billion years of history, from
preCambrian to Permian. The thorite itself was
found in Permian pegmatites.To one side of the
fjord an Ordovician limestone quarry lay,
marked by a smokestack of an accompanying
cement factory; to the other side a FPrmian cliff
of blue syenite loomed over the horizon. "This
is the famous blue schillerizing larvikite used in
so many buildings of the world." Alf told us
(note 5).
WINTER 2001
,..g%.g
