Searching for Sparks

You said you needed sparks. I walked across the cold floor to investigate sources of friction. Near the skirting board, I found a rough grey pebble and the corner of an iron radiator bracket. I held the pebble firmly in my right hand and struck it downward against the bracket edge. The impact made a sharp clink, but no ember appeared. I examined the stone surface. It left a faint white scrape on the iron. I will try different angles and harder mineral edges until something ignites.