How gold is refined and transformed into jewellery

Step 1: Mining and Extraction

Gold is first mined from the earth, often from quartz veins or placer deposits (riverbeds). The ore is crushed and ground into fine particles to release the gold. Chemical processes such as cyanidation or amalgamation (historically using mercury, though now less common due to environmental laws) separate the gold from surrounding rock and minerals.

Step 2: Smelting and Initial Purification

The extracted gold particles are then smelted—heated at very high temperatures (over 1,000°C) in a furnace. This process melts the gold and allows heavier impurities to settle at the bottom while lighter materials are skimmed off. The result is doré gold, a semi-pure alloy usually containing 60–90% gold along with silver, copper, and other metals.

Step 3: Chemical Refining

To achieve higher purity, the doré gold undergoes chemical refining. There are two main industrial methods:

• The Miller Process: Uses chlorine gas to separate gold from impurities, resulting in about 99.5% pure gold.

• The Wohlwill Process: An electrolytic process that passes an electric current through a gold-chloride solution, yielding 99.99% pure gold.

At the end of this stage, the refined gold is known as fine gold, typically 24 Carats.

Step 4: Alloying for Strength and Colour

Pure 24ct gold is soft and easily scratched, so jewellers mix it with other metals to improve durability and create different colours and also to make the gold soft, hard or easy flowing for different applications:

• Copper adds a warm reddish hue (rose gold).

• Silver or zinc creates bright yellow gold.

• Palladium or nickel produces white gold.

The mixture determines the carat value—such as 18ct (75% gold) or 14ct (58.5% gold).

Step 5: Casting and Forming

Technically a gold or silver master pattern is encased in a special rubber and then carefully cut out, Wax is injected into the mould, to produce copies, which are removed and set into a casting plaster before being burnt out. The resulting void is then filled with molten gold to replicate copies of the original master pattern.

Step 6: Crafting and Finishing

Skilled goldsmiths cut, solder, engrave, and polish the gold into the final jewellery piece. Stones may be set, and surfaces are finished to achieve a high polish or texture.

Step 7: Hallmarking and Quality Assurance

Finally, the jewellery is tested and hallmarked to certify its gold content and authenticity. In the UK, for instance, hallmarking is carried out by an official Assay Office to ensure the purity meets legal standards.

From raw ore deep in the Welsh hills to a shining ring on someone’s hand, every piece of gold jewellery undergoes a meticulous journey. One that transforms nature’s raw treasure into an enduring symbol of beauty, heritage, and craftsmanship.