period: Tertiary (65-1.8 million years ago)
excavation site: Szklary mine pit, Ząbkowice Śląskie (Lower Silesia)
Chrysoprase is a mineral coloured green by nickel compounds, a common chalcedony variation with a semicrystalline structure. A seam of chrysoprase in a closed Szklary nickle pit is known as the most famous place of the kind in Poland and Europe. Common forms of chrysoprase occurences are streaks and plates of up to 15 cm of thickness. Uncracked chrysoprases with highest purity levels and intense green colour are used in jewellery.
The piece comes from the collection of Geological Museum of the National Geological Institute – National Research Institute.