Related Clues:

• George had a chop in such a gritty way
• And when you've taken the top off it's all in little bits
• Kind of bag, bank or bar
• Castle-building material
• Beach matter
• Sulphur and silica mostly
• Beach-castle material
• Bunker fill
• Pieces of second-hand quartz?
• Nearly all power unknown is invincible
• God is great
• On the Beach author?
• Very tiny grains of rock
• Grains of quartz
• Sort of paper, piper, castle or martin