Jewelry rhodium plating: complete guide
Why, when and how to rhodium plate your white gold and silver jewelry.
At a glanceRhodium plating for jewelry is an electroplating finishing process widely used across luxury jewelry and horology. Essential for enhancing white gold and protecting sterling silver against tarnish, it deposits a microscopic layer of pure rhodium, one of the rarest, hardest, and most valuable platinum-group metals on Earth. This guide covers the chemistry, durability, and costs in Switzerland.
What is Rhodium and Why is it Used?
Rhodium ($Rh$, atomic number 45) belongs to the platinum group metals (PGM):
- Superior optical reflectance: Imparts an ultra-bright mirror-white finish reflecting over 80% of light.
- Remarkable hardness: Reaches a Vickers hardness of 800 to 1,000 HV (nearly 6 times harder than annealed 18k gold at 130 HV), shielding items from micro-scratches.
- Total chemical inertness: Completely tarnish-resistant and impervious to atmospheric corrosion.
Why White Gold Must be Rhodium Plated
As-cast white gold (75% yellow gold alloyed with silver, copper, and palladium or nickel) is never stark white; it retains a subtle gray or warm champagne hue. Rhodium plating provides the icy white finish expected by retail consumers.
The Workshop Electroplating Process
1. High-luster polish: Rhodium covers no scratches; surfaces must be mirror-polished first.
2. Electrolytic degreasing: Cleaning in an alkaline bath at 6V to strip away polishing compounds.
3. Acid activation: Brief dip in 5% sulfuric acid to remove passivation films.
4. Rhodium galvanic bath:
- Bath temperature: 40 °C to 50 °C.
- Anodes: Platinized titanium.
- Voltage: 2.0 to 3.5 Volts.
- Immersion time: 30 to 60 seconds.
- Deposit thickness: 0.10 to 0.50 micrometers (µm).
Durability and Pricing Overview
| Plated Jewelry Type | Daily Friction Exposure | Re-plating Frequency | Average Cost in Swiss Jewelry Stores (CHF) |
|---|---|---|---|
| Engagement / Wedding Ring | Very high (daily contact) | Every 12 to 24 months | CHF 50 – 90 |
| White Gold Bracelet | High (desk & fabric contact) | Every 2 to 3 years | CHF 70 – 120 |
| Pendant / Locket | Low (rests on skin or cloth) | Every 5 to 8 years | CHF 40 – 70 |
| Earrings | Minimal (no friction) | 10+ years (near permanent) | CHF 40 – 60 |
The Swiss Solution: Palladium White Gold without Plating
Swiss manufactures like Patek Philippe and Rolex increasingly use Palladium White Gold (13–15% Pd). This alloy is naturally gray-white throughout its bulk. It never yellows with wear, making rhodium plating entirely optional.
Frequently Asked Questions (FAQ): Rhodium Plating
Can silver jewelry be rhodium plated?
Yes, rhodium plating on 925 sterling silver is popular because it permanently prevents black tarnishing from atmospheric hydrogen sulfide.
Does rhodium trigger allergies?
No, rhodium is 100% hypoallergenic and acts as a barrier preventing skin contact with underlying nickel traces in older jewelry.
Buy Investment Gold in Switzerland (VAT-Exempt)
Buy and store physical gold in secure Zurich or Geneva vaults at direct live LBMA spot rates.