Authigenic smoky quartz from the Famennian limestones at Łagów in the Holy-Cross Mts

Abstract

Inside smoky and black crystals of quartz from joint fractures in bituminous Famenian limestones at Łagów in the Holy Cross Mts, there occur inclusions containing variable amount of bituminous matter and aqueous solution of salts and gas. The occurrence of bitumen gives quartz its colour. The average temperatures of smoky quartz crystallization were c.70oC,and of black quartz - c. 160-190oC. The veinlets of brown-black calcite, containing analogous inclusions, crystallized under similar conditions which revealed both minerals being connected with aqueous solutions containing dispersed droplets of bituminous matter.