Stakholmen quartz quarry

Visits

1997-10-13
I visited Stakholmen after my week in Bergslagen and Västerås.
It was monday the thirteenth of october and I got a good start in the morning. After having failed (second try) to locate Glasgruvan in Sala I continued to the north for about 100 km.
After some reevaluation of the information that were in my possession (it was snowing) I decided to skip some minor excursions and went straight to Stakholmen. The quarry were mined for quartz and the pieces with too much impurities were put aside at the edge of the forest.
Among these rocks there were some long grey crystals which for a long time were identified as kornerupine. A later reexamination of material from this quarry revealed it to be prismatine, a boron analog of kornerupine.
This is the first location of this mineral in Sweden.

Litterature

GFF 118

Mineral assemblage

Prismatine, enstatite, talc, quartz, phlogopite, dravite, cordierite, plagioklas, manganocolumbite, sillimanite, muscovite, chondrodite.

Prismatine
In enstatite and talc.
Collected 1997-10-13.
(300 dpi, 800x600, 56k)

Prismatine
Another piece of prismatine. Partwise transparent.
Collected 1997-10-13.
(300 dpi, 800x600, 56k)

Chondrodite
In quartz with muscovite and prismatine.
This specimen shows a very strong yellow flourescens.
Collected 1997-10-13.
(300 dpi, 800x600, 50k)

Sillimanite
Sillimanite on quartz.
Collected 1997-10-13.
(300 dpi, 800x600, 55k)

Muscovite
An unusual light green variant of Muscovite.
.
Collected 1997-10-13.
(300 dpi, 800x600, k)

Enstatite
A nice piece of homogenous crystalline enstatite with gray prismatine. The enstatite is slightly less hard than quartz and shows the 85 degrees between the cleavage planes. It is very clear and vary in color from bright white, yellowish to colorless.
The piece is all terminated by fractures or cleavages, no natural crystal surfaces exists.
Collected 1997-10-13.
(300 dpi, 800x600, k)

Cordierite
Cordierite with biotite and some quartz. On the other side of the stone there is a brown aggregate of some unknown mineral.
Collected 1997-10-13.
(300 dpi, 800x600, k)

If you have some questions, suggestions or comments you are welcome to write me a line or two.

Locality index. Main index.

axelsson@acc.umu.se

	Prismatine In enstatite and talc. Collected 1997-10-13. (300 dpi, 800x600, 56k)
	Prismatine Another piece of prismatine. Partwise transparent. Collected 1997-10-13. (300 dpi, 800x600, 56k)
	Chondrodite In quartz with muscovite and prismatine. This specimen shows a very strong yellow flourescens. Collected 1997-10-13. (300 dpi, 800x600, 50k)
	Sillimanite Sillimanite on quartz. Collected 1997-10-13. (300 dpi, 800x600, 55k)
	Muscovite An unusual light green variant of Muscovite. . Collected 1997-10-13. (300 dpi, 800x600, k)
	Enstatite A nice piece of homogenous crystalline enstatite with gray prismatine. The enstatite is slightly less hard than quartz and shows the 85 degrees between the cleavage planes. It is very clear and vary in color from bright white, yellowish to colorless. The piece is all terminated by fractures or cleavages, no natural crystal surfaces exists. Collected 1997-10-13. (300 dpi, 800x600, k)
	Cordierite Cordierite with biotite and some quartz. On the other side of the stone there is a brown aggregate of some unknown mineral. Collected 1997-10-13. (300 dpi, 800x600, k)