Precious Metals Guide

At ECGLOSTY, we want you to feel completely confident in every precious metal purchase. This guide explains the industry standards we follow for purity certification, weight measurement, pricing, and testing—so you know exactly what you are getting and how to care for it.

Understanding Precious Metal Purity

Precious metal purity refers to the proportion of pure metal in an alloy. The higher the purity, the softer and more susceptible to wear the metal becomes, which is why pure metals are often alloyed with other metals for durability in jewelry applications.

Gold Purity

Gold purity is expressed in karats (K) for jewelry, or fineness for investment purposes.

Karats: The karat system divides gold content into 24 parts. 24K gold is 100% pure gold, but it is too soft for most jewelry settings. Common jewelry purities include:

18K Gold: 75% pure gold (750 fineness). Richer color, softer, best for heirloom pieces with careful wear.
14K Gold: 58.3% pure gold (585 fineness). The most popular choice for engagement rings and daily-wear jewelry due to its balance of durability and color.
10K Gold: 41.7% pure gold (417 fineness). Strongest and most scratch-resistant, but paler in color.

Fineness: For investment-grade gold bars and coins, purity is expressed in parts per thousand, commonly as 999.9 (99.99% pure) or 999.99 (99.999% pure) . A fineness of 995.0 (99.5%) is the minimum for London Bullion Market Association (LBMA) Good Delivery recognition.

Platinum Purity

Platinum used in fine jewelry typically enters the workshop at approximately 95% purity (950 fineness) . Platinum is naturally white and does not require rhodium plating, unlike white gold. Its density makes it exceptionally durable and ideal for securely holding stones over decades.

For investment-grade platinum, the standard is 999.5 fineness (99.95% pure).

Silver Purity

Investment-grade silver typically carries a fineness of 999 (99.9% pure) or higher . Sterling silver, commonly used in jewelry, is 925 fineness (92.5% pure silver alloyed with copper for strength).

Weight Conversion and Measurement

The precious metals industry uses the troy ounce as the universal unit of weight, distinct from the standard avoirdupois ounce used for everyday items.

Troy Ounce vs. Standard Ounce

Unit	Grams	Usage
Troy Ounce	31.1035 g	Gold, silver, platinum, palladium
Standard Ounce	28.3495 g	Everyday goods

All precious metal prices are quoted per troy ounce . When you see a gold price of $2,000/oz, that refers to one troy ounce of pure gold.

Common Weight Units for Jewelry

Gram (g): Standard unit for smaller jewelry pieces and gemstones.
Pennyweight (dwt): Used in some jewelry contexts, equal to 1/20 troy ounce or 1.555 grams.
Carat (ct): Used exclusively for gemstone weight, not metal. One carat = 0.2 grams.

Pricing Methodology

Precious metal pricing follows a transparent, market-driven system based on global spot prices plus applicable premiums.

Spot Price

The spot price is the current market price for immediate delivery of one troy ounce of pure metal in unallocated form . The London Bullion Market is the international home of precious metal pricing, with official price fixes occurring twice daily at 10:30 and 15:00 GMT .

Spot prices fluctuate continuously based on supply and demand, investor expectations, currency movements, and geopolitical factors.

Premium

Physical precious metal products carry a premium above the spot price. This premium covers costs including:

Manufacturing and fabrication
Design and craftsmanship
Transportation and secure storage
Certification and assay services
Dealer margin

Premiums vary based on product type, form (bar, coin, round), size, and market conditions. Smaller products typically carry higher percentage premiums than larger bars.

Product Pricing at ECGLOSTY

All ECGLOSTY prices reflect the current market value of the precious metal content plus applicable premiums for design, craftsmanship, and certification. Prices are locked at the time of order confirmation.

Testing and Certification Standards

Every precious metal product should be verifiable for both purity and authenticity. ECGLOSTY adheres to internationally recognized testing and certification standards.

Assay Certification

An assay certificate is a written guarantee from an independent or sovereign assay office confirming the purity and weight of a precious metal product . Assay certificates are issued by :

Sovereign mints (e.g., United States Mint, Royal Canadian Mint, Royal Mint)
Independent assay offices (e.g., LBMA-approved assayers)

A valid assay certificate includes :

Stated purity/fineness
Stated weight
Unique serial number (for bars)
Assayer’s signature or brand
Assay method reference

Products sealed “in assay” with original packaging typically command higher resale value and easier liquidity because authenticity is immediately verifiable.

Testing Methods

Fire Assay (Cupellation): The traditional reference method for gold purity determination, accurate to within 0.01% for gold alloys between 333 and 999 fineness. This is a destructive test requiring laboratory equipment and skilled operators.

X-Ray Fluorescence (XRF): A non-invasive modern method that measures surface composition by X-ray irradiation. XRF does not damage the product and is widely used for verification.

ICP-OES / ICP-MS: Advanced spectroscopic methods used for high-purity metals (999.9+), capable of measuring impurity levels in parts per million.

Hallmarking

In many jurisdictions, precious metal jewelry must bear a hallmark indicating fineness and the responsible manufacturer or importer. Hallmarks are applied by assay offices or authorized manufacturers and are legally required in the UK, EU, and other markets.

Precious Metal Returns Policy

Precious metal purchases are subject to ECGLOSTY’s standard 30-Day Return Policy with the following additional considerations:

Return Eligibility

Items must be returned in original, unworn condition with all packaging, certificates, and documentation.
Assay certificates and grading reports must accompany any returned precious metal or diamond product.
Custom-engraved, resized, or modified items cannot be returned unless defective.
Final sale items are not eligible for return.