Rockfall
A rockfall or rock-fall is a quantity of rock that has fallen from a cliff face or from the roof or walls of mine or quarry workings.
Read on WikipediaDusty grey rubble, where the rocks have fallen in perfect ABBA harmony.
Rockfall is a cool grey, close to green.
It can be described as cool, muted, greyish and dusty.
Set in black, because black reads best on it.
A rockfall or rock-fall is a quantity of rock that has fallen from a cliff face or from the roof or walls of mine or quarry workings.
Read on WikipediaProper noun