Classification of gold

Metals are broadly categorized into two main groups: ferrous and non-ferrous. Ferrous metals, which are iron-based, include pure iron and steel. These materials are widely used due to their strength, affordability, and high production efficiency. However, they are prone to rust and corrosion when exposed to moisture. Non-ferrous metals, on the other hand, do not contain iron and are typically more resistant to corrosion. They can be further divided into three main categories: precious metals, base metals, and alloys. Precious metals like gold, silver, and platinum are valued for their rarity, beauty, and industrial applications. Base metals, such as copper and zinc, are more common and less expensive. Alloys, which are combinations of different metals, are often created to enhance properties like durability or color. Gold, in particular, is one of the most sought-after metals in jewelry making. Its lustrous appearance and resistance to tarnishing make it a popular choice. According to geological reports, gold is considered the rarest metal in the world—except for tantalum, which was discovered in 1802. This rarity contributes to its high value and desirability. Platinum (Pt) and palladium (Pd) are both noble metals with similar chemical properties. However, platinum is more stable and significantly more expensive than palladium. Palladium, while less costly, has extensive use in industries such as automotive and electronics due to its catalytic properties. Silver is another popular metal in jewelry, available in different purities. Sterling silver, also known as 925 silver, contains 92.5% pure silver and is commonly found in the market. Pure silver, sometimes called S999, is used for handmade or high-end pieces but is more expensive and softer than 925 silver. When it comes to gold, its purity is measured in karats (K). One karat equals approximately 4.166% of the total weight. Common choices in the market include 18K and 24K gold. The latter represents pure gold, which can be further classified into 99% pure gold or 99.9% "1000 gold." 18K gold, however, includes other metals like copper, silver, or zinc, which affect its color and hardness. You may see variations such as white gold (often mistaken for platinum), yellow gold, and rose gold, marked with designations like G750. Each piece of jewelry carries a hallmark indicating the metal's composition, usually shown as a fraction or a percentage. This helps consumers identify the quality and authenticity of the item they're purchasing.