Jewelry Materials

Quality You Can Measure.

Most jewelry brands keep material details vague. We publish ours. Below is a full breakdown of the metals, finishes, and crystals used in every Oomiay piece, with the specific construction that makes our jewelry different from the broader plated category.

Heavy Gold+ Rings (18K Gold)

Our gold rings use a proprietary multi-layer construction we call Heavy Gold+. Every gold ring is built from four engineered layers, and the gold itself is the real thing: 2.5 microns of 18K gold, 5x the industry standard for gold plating.

Layer 1: Hypoallergenic brass core. A copper-zinc brass alloy with no nickel. Brass is chosen because it is malleable enough to hold the intricate, sculptural designs that define Oomiay (charm pieces, hand-set crystal settings, organic shapes) which rigid metals like stainless steel cannot achieve.
Layer 2: Silver barrier layer. Before gold plating, a thin layer of real silver is applied to the brass. This step blocks brass from migrating through the gold layer over time (the primary cause of tarnishing in cheaper plated jewelry), helps the gold bond more strongly, and is itself hypoallergenic. Most brands skip this step. It is the same barrier methodology used in high-end vermeil and fine jewelry construction.
Layer 3: 2.5 microns of real 18K gold. Deposited in a controlled process that chemically bonds gold particles to the silver-coated surface. For reference, flash-plated jewelry can be as thin as 0.05 microns. The industry standard for gold-plated jewelry is around 0.5 microns. Oomiay Heavy Gold+ is 2.5 microns, 5x the standard.
Layer 4: Advanced sealing protection. A clear protective seal applied as the final step. It acts as a moisture barrier, adds tarnish resistance, creates a smooth polished finish, and extends the plating's functional lifespan.

.925 Sterling Silver Collection

Our sterling silver pieces are made of genuine .925 sterling silver (92.5% pure silver, 7.5% copper alloy for strength) and finished with rhodium plating.

Rhodium is a precious metal from the platinum family, rarer than gold and trading at roughly twice its price (around $9,000 per ounce in October 2026). In fine jewelry, rhodium plating is typically reserved for solid white gold and platinum pieces. By applying rhodium to our sterling silver, we are using a fine-jewelry-grade finish on an accessible everyday piece. The result is a brighter, more reflective shine than unplated silver, with enhanced scratch resistance and long-lasting tarnish protection.

Rhodium plating is long-lasting but not permanent. The sterling silver base underneath is itself a genuine precious metal that maintains its beauty.

Black Gold Collection

Black Gold is Oomiay's name for our distinctive smoky-dark finish. On rings, Black Gold uses the same four-layer construction approach as Heavy Gold+: hypoallergenic brass core, real silver barrier layer, 2.5 microns of black rhodium plating, and an advanced sealing protection. Same thickness standard. Same 2-year warranty. Dramatic visual difference.

Black Gold earrings, necklaces, and bracelets use the same finish in a deep, smoky-dark color, with quality plating and e-coating protection on the body. Earring posts are stainless steel for hypoallergenic safety. Tennis necklaces and bracelets are hand-linked.

Most "black" jewelry on the market is one of three things: oxidized sterling silver (a patina that fades with wear), PVD-coated stainless steel, or a thin flash dip of black rhodium under one micron over an uncertain base. Our construction is the demi-fine equivalent of how a fine-jewelry black finish is built.

5A Cubic Zirconia and Brilliant Cut Crystal Glass

Every Oomiay piece features hand-set 5A grade cubic zirconia (the highest commercial grade, judged on clarity, cut precision, and light return) and brilliant cut crystal glass for our signature colors (mystic topaz, aquamarine, kombucha green, sakura pink, and others).

Every stone is hand-set by skilled artisans. Hand-setting enables the intricate cluster, charm, and multi-stone designs that machine-set methods cannot replicate. Each crystal is individually placed and secured for better grip, alignment, and retention.

Hand-Linked Tennis Construction

Our tennis necklaces and bracelets are hand-linked, meaning each individual link is crafted and connected by hand rather than stamped from a single track or machine-assembled. This delivers fluid drape, anti-flip weight distribution that keeps the necklace face-up, and more secure individual stone settings. Hand-linked construction is significantly more time and labor intensive than machine track manufacturing, and the result is visibly different.

Earring Posts

All Oomiay earring posts are stainless steel for durability and hypoallergenic safety. Stainless steel posts will not bend, corrode, or irritate sensitive ears. The earring body uses our quality plating with e-coating protection, and all crystals are hand-set.

How We Compare to Industry Standards

Flash plating: as thin as 0.05 microns. The cheapest end of plated jewelry.
Industry standard "gold plated": around 0.5 microns of gold.
Vermeil: sterling silver base with at least 2.5 microns of at least 10K gold plating (US FTC definition). Our gold rings meet the thickness benchmark but sit over brass with a silver barrier rather than a solid silver base, so we do not label them vermeil.
PVD ("waterproof" stainless steel brands): typically 0.03 to 0.08 microns thick, often using titanium nitride or zirconium carbonitride to mimic a gold color rather than depositing actual gold.
Oomiay Heavy Gold+: 2.5 microns of real 18K gold, plus a silver barrier layer, plus an advanced sealing protection. 5x the industry standard for gold plating.

Going Deeper

What is Heavy Gold+? Heavy Gold+ is Oomiay's name for our four-layer ring construction: hypoallergenic brass core, silver barrier layer, 2.5 microns of real 18K gold, and an advanced sealing protection. The industry term for the underlying chemical process is electroplating. Heavy Gold+ is the brand name we use to describe both the construction and the thickness standard.

What is Black Gold made of? Black Gold is the brand name for our smoky-dark finish. The visible plating layer is black rhodium. At the deeper material level, black rhodium plating is produced from a specialized electrolyte bath where rhodium (the platinum-family precious metal used for the bright finish on fine white gold jewelry) is combined with complementary plating metals (typically tin and cobalt) to achieve the deep color and the ductility needed to plate reliably at 2.5 microns. This is the standard approach for producing durable black finishes in fine jewelry. Pure rhodium on its own is too brittle to hold at this thickness.

Why do you say water-resistant and not waterproof? No plated jewelry is truly waterproof. Stainless steel PVD coatings used by "waterproof" brands also degrade over time from chlorine, saltwater, and chemicals. Our jewelry is engineered for everyday life (hand washing, rain, occasional splashes) but we do not market it as waterproof because that would not be honest. Only solid gold approaches genuinely waterproof performance.

What about "green skin"? Green skin is not an allergic reaction and is not harmful. It happens when copper in brass reacts with more acidic skin oils. It is harmless and washes off. Our 2.5 micron plating plus silver barrier prevents this during normal wear. If it does happen, it is a skin-chemistry indicator, and our sterling silver collection is the better fit: solid .925 silver all the way through (92.5% pure silver with a little copper alloyed in for strength, like all sterling), finished with rhodium, with no base metal underneath.