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By contrast, depletion gilding is a subtractive process whereby material is removed to increase the purity of gold that is already present on an object's surface. In depletion gilding, other metals are etched away from the surface of an object composed of a gold alloy by the use of acids or salts, often in combination with heat.
Gold parting is the separating of gold from silver ... The surface was compacted and heavily burnished and indicates early use of depletion gilding.
In depletion gilding, a subtractive process discovered in pre-Columbian Mesoamerica, articles are fabricated by various techniques from an alloy of copper and gold, named tumbaga by the Spaniards. The surface is etched with acids, resulting in a surface of porous gold.
A distinctive depletion gilding technique was developed by the Incas in Pre-Columbian South America. "Overlaying" or folding or hammering on gold foil or gold leaf is mentioned in Homer's Odyssey (Bk vi, 232). [2] Fire-gilding with mercury dates to at least the 4th century BC, and was the most common method until the Early Modern period at least.
The depletion of resources has been an issue since the beginning of the 19th century amidst the First Industrial Revolution.The extraction of both renewable and non-renewable resources increased drastically, much further than thought possible pre-industrialization, due to the technological advancements and economic development that lead to an increased demand for natural resources.
For instance, the consumption of fine jewelry leads to increased mining of gold and diamonds. The extraction of precious metals like gold has degradation effects on the environment, such as loss of forestry during construction of the mining facilities, increased exposure to toxic materials, and disturbance of the nearby ecosystem. [10]
Giurco et al. (2009) [8] indicate that the debate about how to analytically describe resource depletion is ongoing. Traditionally, a fixed stock paradigm has been applied, but Tilton and Lagos (2007) [9] suggest using an opportunity cost paradigm is better because the usable resource quantity is represented by price and the opportunity cost of using the resource.
Ego depletion, idea that self-control or willpower draws upon a limited pool of mental resources that can be used up; Depletion (accounting), an accounting and tax concept used in mining, timber, petroleum, or other similar industries; T-cell depletion, process of T cell removal or reduction