The term "solid 14 kt. gold" or "solid 10 kt. gold" is often used to distinguish the piece from gold filled or gold plated. However, no jewelry is made from pure gold since pure gold is too soft to be useful as jewelry. The gold is mixed with other metals to increase its hardness and determine its color. 14 karat (14 kt.) gold means that the metal is 14 parts gold and 10 parts other metal. For use in jewelry, gold is commonly alloyed with silver, copper and small amounts of zinc to produce various shades of yellow gold and with nickel, copper and zinc to produce white gold. Gold is alloyed with copper to produce pink gold.
The term 14 kt. 1/20 gold filled means that 1/20 of the total weight of the piece is 14 kt. gold. Layers of 14 kt. gold are bonded to the base metal using heat and pressure. Gold filled items are relatively inexpensive as compared to karat gold items and are very durable and will not tarnish.
Gold plated means that either 10 kt. or 14 kt. gold has been bonded to the base metal but will be less than 1/20 of the total weight of the piece. Not as durable as gold filled.
Sterling silver is .925 or 92.5% pure fine silver alloyed with copper. If the silver content is less than 92.5%, it cannot be labeled "sterling silver". Silver is the most highly reflective metal. ALL silver, including the finest .925 sterling silver will tarnish or oxidize when exposed to the air. This can be minimized by storing your silver jewelry in plastic bags to minimize exposure to the air.