Palladium, a lustrous silvery-white metal, is part of the platinum group metals (PGMs). Renowned for its outstanding catalytic properties, malleability, and resistance to corrosion, palladium is among the rarest and most valuable precious metals. Its unique physical and chemical characteristics make it indispensable in various industries.

Platinum, a dense, malleable, and highly unreactive metal, is one of the rarest elements found in the Earth's crust. Its remarkable resistance to wear, tarnish, and high temperature make it an extremely valuable and sought-after metal. Platinum belongs to a group of metals known as the Platinum Group Metals (PGMs), including palladium, rhodium, iridium, osmium, and ruthenium.

The National Gold and Silver Marking Act, also known as the National Stamping Act, plays a crucial role in the United States precious metals industry. Enacted in 1906, its purpose is to protect consumers from misleading claims about the content of gold and silver in items like jewelry and tableware. This federal law maintains the industry's integrity by stipulating accurate marking or 'stamping' of gold and silver items with their metal content, also known as fineness.

Placer gold is a type of gold that has been relocated from its original vein or lode due to weathering and erosion over millions of years. The gold is moved by natural forces such as water or glaciers, causing it to accumulate in crevices or deposits in rivers, streams, or other bodies of water. These locations are known as “placers,” hence the name “placer gold.”

Gold-filled jewelry refers to a specific type of gold jewelry that offers similar durability as solid gold without the hefty price tag. It is created by using heat and pressure to bond a layer of gold to a base metal, often brass or copper, resulting in a piece that has a similar outer appearance as a solid gold item. Unlike gold-plated jewelry, which merely covers the base metal with a thin layer of gold, gold-filled jewelry contains a thicker layer of gold. This makes gold-filled jewelry somewhat more resistant to tarnishing and chipping, giving it a longer lifespan. Unlike typical karat jewelry, however, gold-filled jewelry will have a much lower total precious metal content due to the core base metal content.

Karat gold jewelry is any piece of jewelry made from gold that is not 100% pure, denoted by a karat (K) rating. The karat system is used to express the proportion of gold in an alloy out of 24 parts. Thus, 24K gold is pure gold, while 18K gold contains 18 parts gold and 6 parts of other metals (75% pure), and so on. These other metals, often copper, silver, or zinc, are added to increase the durability and alter the color of the gold.