The Lava Cave can be found to the South-West of Mt Snowpeak.
Within the Lava Cave is the Secret Smithy, an Area where you can purchase Blacksmith wares.
Crafting-wise
Magma Ore Deposits can be found scattered throughout the Area. Magma Ore Deposits can drop Quality Minty Ore and Magma ore.
Large Magma Ore Deposits have the chance to drop Rubies.
A Dragon Scab can be found in the Area.
A Sacred Fire Tree can also be found in the Area. Drops Fire Logs along with a bounty.
Bounties
Monsters
The Lava Golem bounty can be found in the Area, when cashed in this grants 1000 Dosh and a single piece of Magma Ore, or on rare occasions a Lava Pickaxe.
A Blaze Wraith bounty can also be found within the Cave, when cashed in this grants 3600 Dosh and a Giant Fang and possibly a Flame Robe. A Giant Fang can be obtained as a drop.
Mining-Locations
Incandescent Gemstones can be found as a bounty from Amazing Magma Ore Deposits, when cashed in it grants 600 Dosh and a Ruby.
A Dragon Scab can be mined in the Area, when cashed in it grants 1000 Dosh and a Dragon Shard.