From WoWWiki

A simple mineral item usually gathered from mineral veins or deposits and often usable as an ingredient for professions (usually Blacksmithing or Engineering). Stones are also a drop from Earth Elementals, Fire Elementals, and Infernals, corresponding in quality to the mob's level.

Mineable stones

Five types of stone, in order of skill level required to manipulate:

• [Rough Stone] - Copper Veins
• [Coarse Stone] - Tin and Silver Veins
• [Heavy Stone] - Iron Deposits
• [Solid Stone] - Mithril Deposits
• [Dense Stone] - Thorium Veins

Uses for stone

From each stone can be made the correspondent blasting powder (with Engineering); and the correspondent grinding stone, sharpening stone, and weightstone (with Blacksmithing).

• Blasting powder is used mostly for dynamite, bombs, ammo, and products like that.
• Grinding stones are used in recipes for crafting weapons.
• Sharpening stones are used to temporarily buff an edged weapon such as a sword or axe.
• Weightstones are used to temporarily buff a blunt weapon such as a mace.

Other Stone Related Items

• [Smooth Stone Chip]
• [Shiny Polished Stone]
• [Jagged Piece of Stone]
• [Lifeless Stone]
• [Runic Stone]
• [Black Stone]
• [Crystalized Stone Chips]
• [Crystalized Stone]