Calcareous sand

Sand comprising almost entirely of multicoloured, crushed sea shells. Shells are made of calcium carbonate in the form of mineral calcite or aragonite.

The shell fragments react with acid, e.g. white vinegar, to produce CO2 gas. This i llustrates how increased acidity of the oceans can erode the calcium carbonate shells of shellfish, thus threatening their survival.

The reaction with acid, and the sand grains themselves, are best viewed under a magnifying glass or through a stereo microscope using good lighting.

Size: 100g bag

Locality: Upper South Island, New Zealand.