Smelting means to manufacture Crystals, then Runes (A) or (B) which are needed to Craft Items.
If you want to Smelt some Crystals/Runes
You must go to the "Smelting Master Arad", He is in Pillai.

You need 3 Ores of the Same Type to Smelt a Crystal.
You need 3 Crystals of the Same Type to Smelt a Rune.
Smelting Crystals or Runes are 100% successful.
Add the Ores or Crystals in the Box where it says Stone/Crystal and Sheltom
where it says Sheltom, you will also need some gold.

Check the tables below to find where Ores may be found
and how to smelt them into runes.

Ores Can be found in
Violet Ores Battlefield of the Ancients, Forbidden Land
Silver Ores Mushroom Cave, Beehive Cave, Ancient Prison Floor 3
Gold Ores Dark Sanctuary, Greedy Lake
Light-Blue Ores Cursed Temple Floor 1, Cursed Temple Floor 2
Deep-Blue Ores Railway of Chaos, Heart of Perum, Gallubia Valley, Frozen Sanctuary, Kelvezu's Lair
Orange Ores Land of Chaos, Lost Temple
Red Ores Endless Tower Floor 1, Endless Tower Floor 2, Endless Tower Floor 3
Green Ores Endless Tower Floor 3, Ice Mine

  Smelting Crystals Formulas
Result Item Required Ores Required Sheltom
           Violet Crystal            Violet Ore X 3            Transparo X 1
           Silver Crystal            Silver Ore X 3            Murky X 1
           Gold Crystal            Gold Ore X 3            Devine X 1
           Light-Blue Crystal            Light-Blue Ore X 3            Celesto X 1
           Deep-Blue Crystal            Deep-Blue Ore X 3            Mirage X 1
           Orange Crystal            Orange Ore X 3            Inferna X 1
           Red Crystal            Red Ore X 3            Enigma X 1
           Green Crystal            Green Ore X 3            Bellum X 1

  Smelting Runes Formulas
Result Item Required Crystals Required Sheltom
           Violet Rune (A) or (B)            Violet Crystal X 3            Murky X 1
           Silver Rune (A) or (B)            Silver Crystal X 3            Devine X 1
           Gold Rune (A) or (B)            Gold Crystal X 3            Celesto X 1
           Light-Blue Rune (A) or (B)            Light-Blue Crystal X 3            Mirage X 1
           Deep-Blue Rune (A) or (B)            Deep-Blue Crystal X 3            Inferna X 1
           Orange Rune (A) or (B)            Orange Crystal X 3            Enigma X 1
           Red Rune (A) or (B)            Red Crystal X 3            Bellum X 1
           Green Rune (A) or (B)            Green Crystal X 3            Ordo X 1
Note: Runes smelt as (A) or (B) randomly.