Purity of gold is expressed in Karats. The purest form of gold is expressed as 24 carats and is very yellow in colour and soft in texture. Due to this, gold is often mixed (aka ‘alloyed’) with other metals to make it more durable for the purposes of wearing it as jewelry. 

Example of 14 kt is 14 parts gold and 10 parts alloyed metal. 14k white gold and 14k yellow gold have the same gold content and purity (58.5% gold), but the alloys in white gold (and the rhodium plating) make it appear white, while the alloys in yellow gold do not.

Gold Filled: Gold filled jewelry is a fraction of the cost of solid gold and is made by bonding gold to a base metal to give it the appearance of gold. The process involves a high amount of heat and pressure and the resultant gold filled piece is typically more durable than a gold plated piece. However, over time, gold filled jewellery does not wear well and will not hold value like a solid gold piece will.

Gold Plated or Vermeil: Gold Plated jewelry is the lowest quality when comparing all three. The process of plating involves a very thin layer of gold being electrically charged onto a base metal. It has an average lifespan of up to a year (with minimal exposure to moisture). Since it has such a minute amount of gold, any friction will cause the plating to rub off quickly, leaving only a piece of dull metal. Most base metals used in gold plated jewelry tend to turn your skin green or cause allergic reactions.