There are two kinds of sodium lights: Low Pressure (LPS) and High Pressure (HPS). These lamps are mostly used for street lighting as well as industrial uses. The lamp works by creating an electric arc through vaporized sodium metal.
Enhanced Turquoise. Enhanced Turquoise is a natural stone that has only been treated with either chemicals and heat, or just heat to enhance the color and harden the stone. This type of treatment keeps the color from fading over time and makes more of the harder turquoise available for the market.
Turquoise varies in quality from Gem quality to low grade âchalkâ. 1  GEM quality turquoise is HARD. 2  LOW grade turquoise is SOFT.  Turquoise is a hydrated phosphate of copper and aluminum and is formed by the percolation of meteoric or groundwater through aluminous rock in the presence of copper. For this reason, it is often associated with copper deposits as a secondary mineral. Turquoise is most often found in arid, semiarid or desert places.