Like it have happened a couple of times this autumn, today’s trip result was based on a trip with friends ending up in a pegmatite I’ve walked past numerous times, and the only thing I’ve taken from it in the previous times are some fluorites and pictures.

It started last weekend, me having a board meeting in NAGS (Norwegian amateur geological society) on Saturday, and to make those meetings a little more interesting we went out collecting on Sunday 26. October. We going out collecting being Jan Arne Stenløkk, Hans-Christian Berntzen and I. We first went to Sagåsen, and despite the quarry hasn’t been in operation since June it’s still easy to find some good samples here. We found good astrophyllite, cancrinite, thorite (variety orangite), zirsilite-(Ce) and others, and brought also with us some polished slabs of larvikite from the dumps of a small stone industry factory lying nearby the quarry. Then the trip went to AS Granite, since in this quarry it’s also always possible to find something.

We started at level 3, at a pegmatite vein that have been exposed at least a year, as you can see from one of the photos, taken last December as a Christmas greeting-card photo. The previous evening I used a fragment of fluorite from this pegmatite to demonstrate thermoluminisence, as to be used as a great activity on meetings for youth groups. Before reaching the vein we had a look at a small pocket where Ingulv Burvald had collected some pretty amazing thomsonite samples. There where still some nice ones to be found, so while Hans-Christian and I did that, Jan went for the fluorite, getting a surprise. On a larvikite block lying next to the pegmatite he found some leftovers after some other lucky collector, with nice aegirine crystals, which made us two other moves quickly after him. And I think all of us got some pretty good sample with us. Hans-Christian making the find of the day, with a nice terminated aegirine crystal at least 8 cm long!



Going back today, I checked the areas where they worked the quarry, finding nothing new exciting. There where a zircon rich pegmatite at level 4, but all crystals where grown into each other and as zircon usually is in the nepheline-syenite pegmatites, awful fragile and breaking when trying to get them out. So it was obvious that I went down to the fluorite rich pegmatite to look for some more aegirine, and just as I hoped I got out a couple of nice samples. Neither an easy job, as most of the aegirine with their perfect cleavage came out in fragments rather than complete crystals, but some came out complete and even a couple of double terminated too!

Other minerals in this fluorite rich vein, with these great aegirine crystals are calcite crystals (good micros), apatite-(CaF), feldspar crystals and some pseudomorphs after a radiating mineral occurring in the fluorite – I think it might have been a radioactive mineral, giving the violet colour to the fluorite, and some of the remnants look like it might be britholite, and some of the replacement minerals being bastnäsite.

Aegirine crystals in fluorite

Aegirine crystals, largest being 4 cm

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