One Beeswax will melt into 8 Melted Wax.
Beeswax blocks are usually found in packs of 1 up to 34 in many trees, except for Shorewood. They can be harvested without a Power Cell and can also be placed for decorative or even building means. Since R27 in January 2016 they can also be used in Blueprints.
This natural wax will grow more and more over time in tree leaves, starting with Queen Bees that spawn and turn into Beeswax within ca. 3,5 (real-time) hours, no matter if player-characters are online or offline.
Beeswax can be grown from Queen Bees that will occasionally be an additional harvest when taking Beeswax, and sometimes can be found after having spawned on trees/leaves in environments where Beeswax cannot grow from it (like in hot parts of Savannahs).
Queen Bees can be planted on any kind of Wood or Leaves except for Shorewood, Shorewood Leaves, Dark Wildwood Leaves, Logs and corrupted blocks. Currently (as of R27 in January 2016) you don't need more than 1 block any more to plant Queen Bees on to successfully make Beeswax grow.
Still long as planted Queen Bees are fallow (displayed in red letters when looking at the Queen Bee placed in the world) they will not turn into Beeswax no matter what.
If Queen Bees stay fallow after being planted, the environment is currently not fitting to grow Beeswax there. Most often the temperature is too hot there, but Queen Bees will also not grow in too cold climates, on altitudes too high (even if heated up), in Swamplands or areas close to Swamplands (respectively too much Bog Water) - or sometimes for no apparent reason at all, which might be or might not be a bug and can actually sometimes change after another new update.
Beeswax will not change in any way if you throw Fire Bombs or other explosives at it.