Custom Jewelry Manufacturing: Metals, Plating and Why Jewelry Turns Green

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Jewelry is a favourite first product for creators and fashion brands. It's small, light, easy to ship, and the margins can be great.

It's also one of the easiest products to get wrong. The photos look perfect. Then, three weeks later, customers send pictures of green fingers and faded gold.

Almost every one of those problems comes from three choices: the base metal, the plating, and how it was tested. Here's how to get them right.

Step 1: Choose the base metal

The base metal is what's under the surface. It decides the price, the weight, and what happens when the plating wears off.

Base metal	Good points	Watch out for
Stainless steel (316L)	Strong, doesn't rust, good for everyday wear	Harder to make fine details
Sterling silver (925)	Real precious metal, great for "demi-fine"	Tarnishes, higher cost
Brass	Easy to shape, good details, takes plating well	Can turn skin green if plating wears off
Copper	Warm colour, low cost	Turns skin green, tarnishes
Zinc alloy	Cheap, good for cast pieces	Lower-end feel, check for lead and cadmium

The honest truth: the "green finger" problem usually comes from copper-based metals (brass, copper) under thin plating. When the plating wears through, the copper reacts with skin and sweat.

Step 2: Understand plating thickness

Plating is a thin layer of gold, silver or rhodium on top of the base metal. Its thickness is measured in microns (thousandths of a millimetre).

• Flash plating: a very thin layer, often well under half a micron. Looks great at first, can wear off within weeks
• Thicker plating: around 1 to 2.5 microns or more. Lasts much longer, costs more
• Gold vermeil: in the US, this means sterling silver with a gold layer of at least 2.5 microns (and at least 10 karat). Only use the word if it's true
• PVD coating: a very hard, durable colour layer, often used on stainless steel. Good for everyday pieces

Always ask the factory: "What is the plating thickness, in microns?" Put the answer in your order. If they can't answer, that's your answer.

Step 3: Know the rules (nickel, lead, cadmium)

Jewelry touches skin for hours, so many markets limit certain metals.

• Nickel (EU): under REACH, jewelry that has long contact with skin must not release more than 0.5 µg/cm² per week of nickel. For piercing posts, the limit is stricter: 0.2 µg/cm² per week
• Lead and cadmium (EU): REACH also limits lead and cadmium in jewelry parts
• US: children's jewelry has strict lead limits under federal law (CPSIA). Some states, like California, have their own rules for jewelry
• Many brands simply go "nickel-free", which makes marketing easier and reduces skin reactions

Rules are detailed and change over time. Use an accredited testing lab and check the current requirements for each market you sell in.

Step 4: Samples and wear tests

Don't judge jewelry on day one. Judge it on day 30.

Simple tests to run on samples:

1. Wear test: wear it every day for a few weeks. Hands, sweat, hand cream, showers
2. Sweat and salt test: labs can run artificial sweat tests. Quick home version: leave a piece in salty water and check for changes
3. Rub test: rub with a cloth many times and check the plating on edges and corners. That's where it wears first
4. Clasp and ring test: open and close clasps many times. Pull on jump rings. They should not open
5. Colour match: compare pieces side by side in daylight. Gold tones vary between batches

Step 5: Stones, findings and small details

• Stones: check that they are glued or set straight, and that none fall out after the rub test
• Findings: clasps, jump rings and earring posts need the same metal and plating rules as the main piece. A nickel-free necklace with a nickel clasp isn't nickel-free
• Sizes: for rings, agree on the sizing system (US, EU, etc.) before sampling

Step 6: Packing that protects

• Anti-tarnish bags or zip bags for each piece, especially for silver and brass
• A small card or box so pieces don't scratch each other
• Your care card: "Remove before swimming, avoid perfume, store dry." It reduces returns more than you'd think

MOQ and timeline

Stock designs with your logo tag or engraving can start small. Custom designs need moulds or tooling (casting or stamping), and the MOQ is usually per design and per colour. Plan for sampling, a few weeks of wear testing, then production. Plating colour is one of the hardest things to match between batches, so keep a golden sample for each colour.

The bottom line

Jewelry turns green because of a cheap base under thin plating, and nobody tested it on real skin. Choose your base metal on purpose, ask for the plating thickness in microns, follow the nickel and lead rules for your market, and wear your samples before you order.

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