Hedenbergite

Hedenbergite is a calcium iron (magnesium) silicate that often bears a range of green to brown colorations. The crystals are typically opaque and occur in stubby or prismatic aggregates. Inner Mongolia, Russia, and Greece all produce quartz crystals colored green as a result of fibrous hedenbergite inclusions. A variety of hedenbergite crystal forms can be found in Sweden as well; dark-green blocky crystals coming from the Nordmark Odal Field.