How would you explain “stone” in the sentence? She stretched out her left hand towards the handle; but before she had touched it, the glass door too flew open. This time, there was no near-miss. Sixteen unseeing stone of disheveled male slammed into her; she was knocked off her feet and catapulted backwards, handbag flying, arms windmilling, towards the void beyond the lethal staircase. How would you explain “stone” in “sixteen unseeing stone of disheveled male slammed into her”? Thanks!