The "Star of Krageroe" depicted on a polished slab from the same occurrence, locally exhibiting exsolved lamellae of haematite.

The cordierites from this locality are among the most Magnesium- and CO2-enriched species analyzed from the Bamble sector making its pleochroism white to pale bluish. Allotriomorphic cordierite crystals weighing up to 6 kg has been discovered close to this locality. Most of this material is resorbed forming greenish patches consisiting of finegrained intergrowths of talc, kyanite, chlorite and quartz, less commonly also blackberry colored Magnesiodumortierite. Nevertheless, larger gemmy domains are found as a rarity, their pale color turning them into beautiful facetted stones (cordierites from Risør and Søndeled are richer in iron making larger gem cut material look too dark.

Though the "Star of Krageroe" (10.43 ct) is of good gem quality, it still has a few inclusions of sillimanite needles and hexagonal flakes of hematite (normal to [001]) visible through a quality loupe. They are however all fluid inclusion free. This one of the largest cut Cordierites ever to come out of Norway. The rough uncut counterpart of this stone is exhibited at the Mineralogical Collection of the Mining Museum of Kongsberg. A more detailed photograph of this gem on white background may be found as a daughter image (Photo ID 283971).

Both the "Star of Kragerø" and the 2mm plished plate are exhibited at the gem collection of the Mineralogical Mineralogical Museum, University of Oslo.

This photo has been shown 2076 times