Dust rune

Dust runes are combination runes. They count as two separate runes; one Earth rune and one Air rune. Thus, any spell requiring one Earth rune, one Air rune or both will spend only one Dust Rune.

Dropping monsters

 * }

Runecrafting Dust Runes
At Runecrafting level 10 or higher, they can be crafted in either of two ways:
 * Pure essence, Earth runes and an Earth Talisman to the Air altar or
 * Pure essence, Air runes and an Air Talisman to the Earth altar.

Players receive 8.3 experience for combining Earth runes at an air altar and 9 for combining Air runes at an Earth altar. Combinations have a 50% success rate (or 100%, if the player is wearing a binding necklace), and the talisman is consumed in the process (unless the player uses the Lunar spell Magic imbue).

As Monster drops
Dust runes are dropped by Flesh Crawlers, Spiritual mages, and all of the statue types in Bandos' throne room. However, Flesh Crawlers are most likely the best as they are low levelled and have no requirements in Slayer or Quests. They are also fairly common.

Spells

 * Earth Strike
 * Earth Bolt
 * Earth Blast
 * Earth Wave
 * Earth Surge
 * Crumble Undead
 * Lumbridge Teleport
 * Teleport to House

Trivia

 * As with all combination runes, the most amount needed for a spell is 30, for the Charge Orb spell series.
 * They are currently the cheapest combination rune and are actually cheaper than earth runes and air runes together.
 * The value of 1 Dust rune in Investment Credits in Mobilising Armies is 7 Investment Credits.
 * There was once a bug where you use up 2 dust runes if you have more than one dust rune when using the teleport to house spell; this glitch has been fixed.
 * The Dust runes inventory icon, along with the other combination runes, was unaffected by the update on 9 June 2010. The other runes were slightly twisted.
 * Due to the large number of Flesh Crawler bots the price of dust runes have at times fallen below the price of earth runes. Depending on the market they can be used to replace Earth runes.
 * In combination with a Mystic Steam Staff or Steam Battlestaff, dust runes make a great way to provide access to all 4 elemental runes with just 2 items