Jinshajiangite from the Norra Kärr alkaline intrusion, Jönköping, Sweden

Abstract

The second world occurrence for jinshajiangite has been encountered at Norra Kärr, where the mineral appears as tabular grains up to 4 mm long, essentially in albite veinlets. Associated phases are, inter alia, magnesio-arfvedsonite, aegirine, fluorapatite and rosenbuschite. Refinement of the monoclinic unit-cell parameters gave a = 10.696(2) Å, b = 13.800(5) Å, c = 20.705(3) Å, β = 94.96(2)° and V = 3044.7(5) ų. The Norra Kärr jinshajiangite is chemically distinguished from the type material mainly by a higher Fe²⁺/(Fe²⁺ + Mn) ratio. It is interpreted as a late-magmatic product related to fractionation.

Keywords:

• Jinshajiangite
• alkaline magmatism
• Norra Kärr
• Sweden