abstract
abundance
ash
background
black
burning
carbon
charcoal
coal
cube
dark
dirty
ecology
effect
energy
environment
extract
fireplace
flame
fossil
fuel
gas
geology
grill
heat
hot
industrial
lignite
manufacturing
material
metallurgical
mineral
nature
power
prices
production
raw
resource
rock
rough
shiny
smoke
solid
space
stone
stove
texture
wood
worker