Extracting gold from jewelry involves dissolving the gold in a strong acid mixture, then recovering it from solution as pure metal. The most common method used by small-scale refiners is aqua regia, a combination of hydrochloric and nitric acid that is one of the few liquids capable of dissolving gold. The process is straightforward in concept but involves serious chemical hazards, and the amount of gold you recover depends entirely on the karat of your starting material.
How Much Gold Is Actually in Your Jewelry
Before you start, it helps to know what you’re working with. The karat stamp on a piece of jewelry tells you exactly what percentage is pure gold, and the rest is base metal alloy (usually copper, silver, nickel, or zinc). For every gram of jewelry:
- 18K contains 750 milligrams of pure gold (75%)
- 14K contains 583 milligrams of pure gold (58.3%)
- 10K contains 417 milligrams of pure gold (41.7%)
So 10 grams of 14K gold scrap, roughly the weight of a couple of rings and a small chain, would yield about 5.8 grams of pure gold. That context matters because the chemicals, equipment, and time involved make this impractical unless you’re processing a meaningful batch. Most hobbyist refiners accumulate scrap over time and process it all at once.
Preparing the Jewelry
Remove any stones, clasps, or non-metal components before you begin. Gemstones can be damaged or destroyed by acid, and non-gold parts (stainless steel spring bars, for instance) will contaminate your solution and waste your chemicals. If pieces contain solder joints, those are fine to leave in; the solder will dissolve along with the alloy metals.
Cut or break larger pieces into smaller fragments. More surface area means faster dissolution and less acid needed. Some refiners flatten pieces with a hammer or snip them into small bits with jewelry shears.
The Aqua Regia Method
Aqua regia is a mixture of 3 parts hydrochloric acid to 1 part nitric acid by volume. The nitric acid oxidizes the gold, and the hydrochloric acid reacts with those gold ions to pull them into solution. Neither acid can dissolve gold on its own; the combination is what makes it work.
Always add the nitric acid last. Start by placing your gold scrap in a heat-resistant glass beaker (borosilicate or Pyrex), then pour in the hydrochloric acid. Add the nitric acid slowly and in small increments. The reaction produces toxic reddish-brown fumes (nitrogen dioxide), so this must be done outdoors or under a proper fume hood. Never in a kitchen, bathroom, or any enclosed space.
The solution will begin to fizz and turn dark as the metals dissolve. Gentle heating on a hot plate speeds the process, but avoid boiling. For a small batch of 10 to 20 grams of jewelry scrap, dissolution can take anywhere from 30 minutes to a few hours depending on the size of the pieces and the temperature. You’ll know the gold is fully dissolved when no solid gold-colored metal remains. Any white or gray residue left behind is typically silver chloride, which is insoluble in aqua regia and can be filtered out.
Removing Excess Nitric Acid
This is a step many beginners skip, and it causes problems. Leftover nitric acid in your solution will re-dissolve the gold when you try to precipitate it. The standard approach is to add small amounts of urea to the solution. When urea hits the liquid, it reacts with the nitrogen compounds and produces bubbles. You keep adding small pinches until the bubbling stops, which signals the excess has been neutralized. Don’t overdo it, as too much urea will degrade the acid balance if you plan to reuse the solution.
Recovering the Gold From Solution
Once filtered and neutralized, your solution contains dissolved gold in a yellowish or orange liquid. To get solid gold back out, you add a reducing agent that forces the gold to drop out of solution as a fine brown or black powder.
Sodium metabisulfite is the most popular choice for hobbyist refiners. You dissolve it in a small amount of water and slowly stir it into the gold-bearing solution. The gold precipitates almost immediately as dark particles, but you should let the mixture sit for at least 30 minutes to allow complete settling. Some refiners wait several hours or overnight to make sure they’ve captured as much gold as possible.
After settling, carefully pour off or siphon the liquid (now mostly spent acid with dissolved base metals) without disturbing the gold powder at the bottom. Rinse the powder several times with distilled water to remove acid residue, then dry it. What you have at this point is gold powder that can be melted in a crucible with a torch or small furnace into a solid button or bead.
What Purity to Expect
A single pass through aqua regia and precipitation typically yields gold in the range of 99.5% to 99.9% purity, depending on how carefully you filtered, neutralized, and washed the precipitate. Small amounts of copper or other metals can carry through if the process is rushed.
Professional refineries achieve 99.97% purity (often written as 999.7 fine) using electrolytic refining, where dissolved gold is plated onto pure gold cathodes in an electrolyte bath. That level of purity isn’t realistic with home equipment, but a careful chemical process gets remarkably close.
Safety and Legal Considerations
This process involves concentrated acids that cause severe chemical burns on contact and produce fumes that can damage your lungs permanently. At a minimum, you need chemical-resistant gloves (nitrile won’t hold up; use neoprene or butyl rubber), splash-proof safety goggles, a full-face respirator rated for acid gases, and a well-ventilated outdoor workspace. Keep a supply of baking soda and water nearby to neutralize any spills on skin or surfaces.
The spent acid solution is hazardous waste. It contains dissolved heavy metals (copper, nickel, lead, zinc) and residual acid. Pouring it down a drain is both dangerous and illegal. In the United States, even small-quantity generators of hazardous waste are subject to EPA regulations. You’re required to determine whether your waste qualifies as hazardous, and spent aqua regia almost certainly does due to its acidity and metal content. Proper disposal means collecting it in labeled, chemical-resistant containers and arranging pickup through a licensed hazardous waste handler. Many communities offer periodic household hazardous waste collection events that accept small quantities.
Is It Worth Doing at Home
For most people with a handful of old rings or broken chains, the honest answer is no. A reputable gold buyer or refiner will pay you 85% to 95% of the gold’s melt value, and you avoid the cost of chemicals, equipment, and waste disposal. The math changes if you’re regularly accumulating scrap, buying lots of mixed jewelry, or processing karat gold as a side business. In those cases, refining your own material can increase your margin significantly, provided you invest in proper safety equipment and learn to handle the chemistry consistently.