http://miningartifacts.homestead.com/minerscandleholders.html

"Prior to the mid-1800s, miners secured candles to their caps or the rocky walls of the mine using a clump of clay. Sometime in the 1860's, however, Comstock area miners invented the miner's candlestick by bending the end of a spike to hold the candle. The spike then could be jabbed into wooden support beams or crevices in the stone walls to light the way. The first candlestick was patented in 1872 and sometime soon after a hook was added to the many emerging designs. Like the lump of clay, the hook on the candlestick enabled the miner to attach a candle to his cap, creating a 19th century version of a headlamp."