Crystallized Earth

Source
Dropped by various earth elemental and golem themed creatures, such as:
 * Brittle Revenant in The Storm Peaks
 * Lifeblood Elemental and Sholazar Guardian in Sholazar Basin
 * Rampaging Earth Elemental and Iron Rune Golem in Howling Fjord
 * Ormorok the Tree-Shaper in The Nexus

Found while mining Cobalt and Rich Cobalt Deposits, Saronite and Rich Saronite Deposits, and Titanium Veins.

Crystallized Earth as an ingredient

 * (1 Eternal Earth = 10 Crystallized Earth and vice versa)

Alchemy

 * Elixir of Protection
 * Mighty Arcane Protection Potion

Blacksmithing

 * Chestplate of Conquest
 * Legplates of Conquest
 * Tempered Saronite Breastplate
 * Tempered Saronite Helm
 * Tempered Saronite Legplates
 * Furious Saronite Beatstick

Enchanting

 * Enchant Shield - Mighty Stamina

Engineering

 * Overcharged Capacitor
 * Shatter Rounds

Jewelcrafting

 * Bloodstone Band
 * Crystal Chalcedony Amulet
 * Crystal Citrine Necklace
 * Sun Rock Ring

Tailoring

 * Frostsavage Belt
 * Frostsavage Boots
 * Frostsavage Bracers
 * Frostsavage Cowl
 * Frostsavage Gloves
 * Frostsavage Leggings
 * Frostsavage Robe
 * Frostsavage Shoulders