Traumatic optic neuropathy (TON) refers to an acute injury of the optic nerve secondary to trauma. The optic nerve axons may be damaged either directly or indirectly and the visual loss may be partial or complete.
In Minecraft, emerald ore is very hard to find and is found in small deposits in the Extreme Hills biome. You can usually find emerald ore between 13 and 31 blocks below the ground and close to lava. So if you see a pool of lava in the Extreme Hills biome, that is a great place to start mining downward.
A variety of Beryl. A green gem variety of Beryl, highly sought after as a precious gem stone. The majority of the world's gem quality Emeralds come from the Muzo area of Colombia. The colour in Emerald is caused by trace amounts of a chromophore such as Chromium or Vanadium.