Margarosanite, Wollastonite, and Calcite from Sweden

Contributed by: Michael Crawford
minID: QDM-7LL
Date: Feb 10th, 2026
Locality: Jakobsberg Mine, Jakobsberg ore field, Nordmark mining district, Filipstad, Värmland County, Sweden (See on Mindat)
Size: 10 x 12 cm

Description:
A multi-color slab from the Jakobsberg Mine, Filipstad, Varmland County, Sweden. The slab containsnthe fluorescent minerals margarosanite (Ca₂PbSi₃3O₉), wollastonite (Ca₃(Si₃O₉)), calcite (CaCO₃), and cymrite (BaAl₂Si₂(O,OH) ₈ · H₂O). The slab also contains scattered grains of non-fluorescent native copper. These minerals are sometimes referred to as the Swedish Flag assemblage because of the bright blue (margarosanite) and yellow (wollastonite) fluorescent colors under shortwave ultraviolet light.

The slab contains two types of margarosanite. Both types fluoresce light blue under shortwave light, but their emission spectra show they have different signatures in their ultraviolet fluorescence. The larger crystals have a prominent peak in the ultraviolet with a maximum at 315 nm. The other type has a smaller peak at 319 nm and a broad peak with a maximum in the visible range at 435 nm. This second type has small needle like crystals in contact with the calcite and thin veinlets near the top of the slab. In the false color image of ultraviolet fluorescence, the larger crystals appear violet and the needle like crystals and veinlets are red. The red color in the false color image and emission spectra are like other margarosanite specimens from Franklin, New Jersey and Jakobsberg, Sweden. The mindat post of this slab states that the margarosanite and wollastonite replace barysillite (Pb₈Mn²⁺[Si₂O₇]₃). The crystals retain the shape of the original barysillite.