Power and glory, at Cape Bridgewater near Portland, on Victoria's west coast, Australia. The sun starts to set as powerful seas smash into the cliffs. The volcanic black rock at the base of the cliff is formed mainly from basalt, and scoria which is purple in colour. June 2003.
Copyright © Joe Mortelliti Photography
Scoria is a highly vesicular - that means that it is full of holes, like a sponge - , dark coloured volcanic rock that may or may not contain crystals. It is typically dark in colour, generally dark brown, black or purplish red, It is related to basalt and is often found near basalt rocks.
The rocks at Cape Bridgewater near Portland are made up of both basalt and scoria, plus lots of limestone in the area of the Petrified Forest.
More info on scoria and basalt in Wikipedia