A tal rune is a low tier rune that can be socketed into armor and weapons. You can cube 3 ith runes together to get a tal rune. You can also obtain a tal rune from normal countess.
A tal rune requires level 17 to use.
Horadric cube recipes with tal runes
transmute 3 tal runes to create a ral rune
transmute normal body armor, a tal rune, a thul rune, and a perfect topaz to create a socketed body armor of the same type
transmute normal shield, a tal rune, an amn rune, and a perfect ruby to create a socketed shield of the same type
transmute normal unique armor, a tal rune, an shael rune, and a perfect diamond to create an exceptional unique armor of the same type