Pääkkönenite is a metallic grey mineral with the molecular formula Sb2AsS2. It is named after Veikko Pääkkönen (1907–1980), a Finnish geologist. It is a fairly rare mineral and some number of specimens were discovered as an association with the spectacular new kermesites (2002) from China.
General Information
It is silvery-gray metallic, elongated but platy, crystals in spherical aggregates associated with dolomite and kermesite. The identification of this mineral has been confirmed by single-crystal X-ray diffraction.
- Category: Sulfide minerals
- Formula: Sb2AsS2
- Crystal system: Monoclinic
- Crystal class: Prismatic (2/m)
- Color: Grey
Properties
- Tenacity: Brittle
- Mohs scale hardness: 2.5
- Luster: Metallic
- Streak: Grey with brownish tint
- Diaphaneity: Opaque
Occurrence: In hydrothermal mineral deposits with other Sb–As-bearing minerals.
This locality is better known for the large world class kermesite crystals that it has produced than its pääkkönenite specimens. So far it would appear that the pääkköneite has been recognized on only a few specimens of well crystallized stibnite and kermesite from the locality. The specimen was trimmed a little to make the it more saleable before it was known that the specimen contained the rare mineral. The original specimen on which this new find was discovered was on a crust were well crystallized stibnite and kermesite were associated with sharp micro crystals of yellow valentinite.
Association: Arsenopyrite, arsenic, l¨ollingite, stibnite, antimony (Kalliosalo deposit, Finland); stibarsen, arsenic, stibnite, sphalerite, siderite, quartz (Pˇr´ıbram, Czech Republic); vaughanite, stibarsen, realgar, arsenic (Hemlo mine, Canada).
