Fire charges can, unlike Flint & Steel, be used on non-solid, non-flammable top-surfaces. I have tested it on the following:
Stone-type slabs/stairs/walls (not upside down)
Nether brick fences, iron bars and glass panes
Gold/iron/stone pressure plates and stone buttons
Levers, torches, end rods, turtle eggs, sea pickles and flower pots
Soulsand, grass paths, farmland and (stacked) snow layers
Cactus, grindstones, anvils, bells and stone cutters
Upon using the Fire Charge on the top surface of these blocks, a fire block will be briefly seen before flickering out. The Fire Charge is, unless in Creative mode, consumed.
To replicate:
1. Obtain a Fire Charge and Flint & Steel, and place any of the above mentioned blocks.
2. Use (Right-Click) the Fire Charge on the top surface of the block. (In the case of some blocks, this may require you to Shift+Right-Click.) Do this in Survival mode.
3. Observe that a fire is indeed placed, and that the Fire Charge is consumed.
4. Repeat step 2. with the Flint & Steel. Observe that nothing happens.
It should be noted, that the fire charge can also be placed in Creative, but does not consume the fire charge.
Duplicate of MC-171257