Magma blocks are the light emitting blocks found in the nether that causes the fire damage when stepped on.
To make magma blocks you’d need Slime Ball, Blaze Rod, Blaze Powder and Magma cream. Please follow the following steps to make Magma Block.
In order to make a magma block first of all you will need to find and kill slimes. Look for the slimes in swamp biomes and kill them to get at least 4 slime balls. You need to be very active to kill them because they bounce a lot.
Enter in Nether to kill Blaze
The next thing you need is blaze rods. Go into the nether and kill blaze in order to get 2 blaze rods.
Go forward towards the nether fortress and find blaze to kill and get blaze rods.
Now you have to make blaze powder. Exit from the nether and make your way to the crafting table to craft 4 blaze powder. One rod can make two blaze powders. Add blaze rod in the center of the crafting area to get blaze powder.
And then add 4 slime balls and 4 blaze powder on the crafting grid to get 4 magma creams. Add these creams into inventory.
Open up crafting table once more and add 4 magma creams in four adjacent cells on 3*3 crafting grid. You will get a magma block.