Regardless of the fact that it'd have to be extremely balanced, but you have to keep in mine the spawn rate and find rate of each ore.
Coal spawns closer to the surface and is extremely easy to mine and find, whereas diamond, however, is not as easy.
It'd be much easier to make diamonds, but it'd somewhat kill the bother of actually finding diamonds.
Just mining coal that you find on the surface, and then compressing it to find diamonds is just too easy.
Bellows: Right clicking with it in hand causes a mob to be knocked back two blocks without any damage.
Made from 3 wool and four iron ingots.
It is needed to craft the Blast Furnace.
Pressurized wall: Pressurized walls have the hardness and blast resistance of of obsidian, but can be moved by pistons.
Made from 1 Iron block surrounded by four obsidian and four Hardened Clay (Any Color). Creates 2 Pressurized walls.
Blast Furnace: A high pressure furnace that functions more efficiently than a normal furnace. Takes up two blocks when placed.
The extra heat and pressure is due to the pistons compressing the material, while an additional layer of iron combined with the bellows helps the furnace build up to a higher temperature. The obsidian acts as an insulator to keep the heat from escaping too quickly. Crafted from a furnace, two pistons, five Pressurized Walls, and one billows.
Advantages: The Blast Furnace cooks things twice as fast as a normal furnace and is also able to cook things that a normal furnace couldn't.
Disadvantages: Only Coal, Coal Blocks, and Lava have enough heat to be able to sustain the Blast furnace's reaction, and due to the extreme heat, Fuel gets consumed faster than it would in a regular furnace; thus one piece of coal could only cook 4 iron ores in a blast furnace. Also, the Blast Furnace has durability; when its durability reaches 0, if the blast furnace still has any heat left within it, It will explode with the equivalent range and force of 1 piece of TNT.
Now here is the part you all have been waiting for... Coal blocks can be put into a blast furnace, which will smelt it into three diamonds. However, it takes at least one coal block worth of fuel in order to give the diamonds time to smelt.
Well guys, what do you think? Is this balanced enough for you?
Everyone is so negative on this thread, there is ways to not make it overpowered and honestly the initial idea of a stack of coal ore turning into a single diamond? I say that's fair. I mean I don't know about anyone else but I never mine coal so I rarely have more than 1 stack, not to mention the work of getting silk touch for the coal ore. Also the compressor would obviously need to be crazy expensive. like maybe it costs 4 diamond blocks, 4 pistons, and a magma block? that's 36 diamond to make diamonds whenever you get enough coal ore. If thats still too op then just require more ore to be needed. like maybe it has a 3x3 crafting grid and you have to fill it with stacks of coal ore (or maybe stacks of blocks of coal) to get just one diamond. If THAT is still too op lets say it takes days in minecraft? like the compression time takes a very long time but smelts coal and fuel at the same rate as a furnace and if it runs out of fuel the process restarts so you have keep it fed. To just say turning coal into diamonds is op seems a little too rushed to judgement as there are many ways the mechanic could be balanced in the three factors of: material cost, time of process, and outcome. I don't think in any way 5184 coal (9 stacks of blocks of coal) equaling 1 diamond is op. If diamonds are made rarer something will need to be done to make them still accessible, unless the way they make them rarer is by making diamond level harder to get too.
Coal can be farmed from wither skeletons, so the processes will be able to be automated.
I don't consider this to ever be a valid argument against something - no matter how you put it automated farming is overpowered and has no place in the game (a game called "Mine"craft, where the majority of players do very little actual mining) - which is why my own version severely nerfs it, ranging from mob spawning (much slower than vanilla, but still more than enough to maintain the mob cap under normal conditions, while farms perform 4-12 times worse) to mobs only dropping "mineral/resource" drops if directly killed by a player, and Looting only working if on the item that directly dealt the killing blow (no bows, splash potions, TNT, etc):
protected void dropFewItems(boolean recentlyHit, int looting)
// Wither skeletons only drop coal if killed by a player
if (this.getSkeletonType() == WITHER)
int count = this.rand.nextInt(3 + looting) - 1;
for (int i = 0; i < count; ++i)
// Removed unnecessary 1 chunk border around spawning chunks, reducing range from 7 to 6
// (169 vs 225 chunks vs 289 in vanilla; making range circular further reduces chunks to
// 121, or only 41.9% of vanilla; and only 1/4 of these can spawn mobs in a given cycle).
this.eligibleChunksForSpawning.put(new ChunkCoordIntPair(cx, chunkZ + z), Boolean.valueOf(((cx & 1) | ((chunkZ + z) & 1) << 1) == chunkSet));
// Slows down individual spawn attempts by a factor of 3 if number of mobs is substantially below
// the cap (overall 12 times slower than vanilla) to reduce wasted attempts and nerf mob farms.
int attempts = (entityCounts[var36] < mobCap / 2 ? 1 : 3);
// Looting only works if the player directly dealt damage (not via bow/arrow or potions)
int looting = (var2 instanceof EntityPlayer && !(par1DamageSource instanceof EntityDamageSourceIndirect) ? CustomEnchantmentHelper.getLootingModifier((EntityLivingBase)var2) : 0);
// dropLoot controls whether mobs spawned from spawners drop anything while iron golems only
// drop loot if killed by a player. Witches only drop redstone and glowstone and zombie pigmen
// only drop gold nuggets if killed by a player (overridden here as their classes are not modified).
if (this.dropLoot && (this.recentlyHit > 0 || !(this instanceof EntityIronGolem)))
if (this instanceof EntityWitch)
this.dropWitchItems(this.recentlyHit > 0, looting);
else if (this instanceof EntityPigZombie)
this.dropPigmanItems(this.recentlyHit > 0, looting);
this.dropFewItems(this.recentlyHit > 0, looting);
("dropLoot" makes mobs spawned from mob spawners not drop anything, including XP, if too many spawn within a given time interval, likely only to occur if somebody tries farming them, so even though spawners spawn mobs MUCH faster than in vanilla (so dungeons, etc are actually challenging) they aren't very good for farming)
(fun fact: Mojang made iron golems and zombie pigmen require a player kill to drop their respective resources in a 1.8 snapshot - which should have not been reverted, no matter how much the community hated it - just as they did not revert the even more controversial combat changes; ironically, 1.9 also nerfed enchanted golden apples, likely because of gold farms making them too OP)
That said, the amount of coal required to make this balanced would make it impractical for most players - I mine more than 2,000 coal per play session but only around 15 diamonds, a ratio of 133 to 1 (the ratio for branch-mining is closer to 10 to 1 but caving yields a lot more coal over time), and you'd want to require much more coal so mining actual diamond ore is still the most effective way to find diamond (or villager trading, which IMO already makes diamond ore worthless other than for the few uses that need actual diamonds, and this is one reason why TMCW nerfs diamond and adds a new top-tier resource which can only be mined):