Three Zones of a Candle Flame
- Innermost Zone: Surrounds wick; contains unburnt wax vapors; black in color; least hot.
- Middle Zone (Luminous): Incomplete combustion; yellow color; moderately hot; leaves soot.
- Outermost Zone (Non-luminous): Complete combustion; blue color; hottest zone (used by goldsmiths with metallic blow-pipe).
