Treasure (from Greek θησαυρος; thesaurus, meaning "a treasure of the chest", is a cognate) is a concentration of riches, often one which is considered lost or forgotten until being rediscovered. Some jurisdictions legally define what constitutes treasure (such as in the English Treasure Act 1996).
The phrase "blood and treasure" or "lives and treasure" has been used to refer to the human and monetary costs associated with various (usually state-initiated) endeavours such as space exploration or war.
Searching for hidden treasure is a common theme in legend and fiction, but real-life treasure hunters exist, and seek lost wealth for a living. Spanish treasure lost from the Spanish treasure fleet consisted of gold, silver, jewels (especially emeralds) and also cocoa, vanilla and brazilwood.
Archaeologists are sometimes described as treasure hunters, especially those from the 19th Century, although they themselves rarely wish to be associated with the term. Treasure hunters are often accused by archaeologists of pillaging ancient sites in their quests, destroying valuable information in the process.
Legally permitted shipwreck salvage under the direction of qualified archaeologists and the subsequent sale of artifacts and treasure by the salvors has been defended as ethical by pioneer underwater archaeologist E. Lee Spence. Spence argues that properly supervised treasure hunting can be a way to fund archaeology and save shipwrecks before they are destroyed by looters and/or lost or destroyed through manmade or natural forces. Spence casts the argument in terms of capitalism versus socialism in underwater archaeology.
Illegal sales of antiquities to foreign buyers are also attributed to illicit treasure hunting.