We currently have 3 in stock.
Greywacke sand consisting of quartz, orthoclase and plagioclase feldspars, calcite, iron oxides and graphitic, carbonaceous matters and other materials.
Greywacke is 'New Zealand's rock', being the most common, and forming massive geological structures such as the Southern Alps. It originally formed from eroded sediments along eastern Gondwana.
Greywacke is used for roading, concrete making, pavements and erosion control.
The small quantities of iron oxide gains present can be picked up with a magnet.
The surprisingly multicoloured mineral grains are best viewed under a magnifying glass or through a stereo microscope using good lighting.
Size: 100g bag
Locality: Upper South Island, New Zealand.