Usually jasper occurs only in relatively small deposits, but in the Guiana Highlands, the intrusions of magma into the sedimentary bedrock have led to the formation of immense slabs of the stone that sometimes are hundreds of meters long. In the most spectacular of all the jasper creeks, a small stream flows over a succession of low cascades which display different coloured layers of crimson, scarlet and orange jasper. In flat areas of the stream the water has carved parallel grooves and channels in the surface of the jasper bedrock and in the shelter of the grooves, black algae grow and form peculiar black strips which give the bedrock a striped appearance similar to tiger skin.
The true brilliance of the jasper is apparent only when sunlight shines directly on wet stone. When sunlight shines on the Firestone Creek, the magnificence of the cascades is revealed and the bedrock glows crimson and orange.
Many small streams throughout the Guiana Highlands cascade over layers of jasper or red hematite, but the Firestone Creek exposure of jasper is the largest and most spectacular of all.