How do i mine diamonds?

First up, be aware that diamonds are vary rare in Minecraft (~0.08% of all blocks in the game in ore form)… So expend to do A LOT of mining & it's pretty dangerous as well… So make sure you're well prepared.

Diamond Ore occurs near the bottom of the world, generally at heights (or layers) of 16 or lower. It is possible (albeit extremely improbable) to find ore between heights of 17 - 20… But it's not the general rule.

The "ideal zone" is around heights of 12 - 16 as lava pools tend generate around heights of 10 or lower, making it a bit more hazardous.

How you get down there to mining is generally up to you, but you'll likely want to have the following on hand.

* Around 10 pickaxes (with at least one being iron or better)
* Water bucket (to neutralize lava)
* Stack or two of torches

Other items you may want to have to help survive & get around easier would be…
* Set of armor + weapon (to help survive against run-in with hostile mobs)
* Ladders (to make the trip up/down easier)
* Chests (to help unload unwanted block)
* Sticks + crafting table (to craft more tools on the go)
* Furnace + char/coal (to smelt any iron ore you run into)

You may want to do some more research on this, but I hope this helps to focus your efforts.

First you need to get an iron pickaxe to mine the diamonds and you need 26 diamonds for full diamond set