Metal Types and Weights

CoinDuffle is built from the ground up for the precious metals market. Every product can be tagged with its metal type and weight, enabling powerful features like metal-based dynamic pricing, metal-specific search filtering, and automated spot price tracking.

Supported Metal Types

CoinDuffle supports the four primary precious metals traded in the bullion market:

Gold

• Symbol: Au
• Spot price source: LBMA / COMEX
• Common products: American Gold Eagles, Canadian Gold Maple Leafs, Gold bars, Krugerrands, Pre-1933 US gold coins
• Common purities: .999 (24K), .9167 (22K, used in American Eagles), .900 (21.6K, used in pre-1933 coins)

Silver

• Symbol: Ag
• Spot price source: LBMA / COMEX
• Common products: American Silver Eagles, Canadian Silver Maple Leafs, Silver bars, Junk silver, Silver rounds
• Common purities: .999, .9999, .900 (90% US coins), .400 (40% Kennedy halves)

Platinum

• Symbol: Pt
• Spot price source: LBMA / NYMEX
• Common products: American Platinum Eagles, Canadian Platinum Maple Leafs, Platinum bars
• Common purities: .9995, .999

Palladium

• Symbol: Pd
• Spot price source: LBMA / NYMEX
• Common products: Canadian Palladium Maple Leafs, Palladium bars
• Common purities: .9995, .999

Weight Units

You can enter product weights in any of these units — CoinDuffle will convert as needed for price calculations:

Troy Ounces (oz t)

The standard unit for precious metals trading. One troy ounce equals approximately 31.1035 grams.

• Most bullion coins are denominated in troy ounces (1 oz, 1/2 oz, 1/4 oz, 1/10 oz)
• Spot prices are quoted per troy ounce
• This is the most common unit you'll use

Grams (g)

Common for smaller products and gram-denominated bullion:

• PAMP Suisse bars (1g, 5g, 10g, 50g, 100g)
• Small gold bars
• Fractional and gram-weight gold products

Kilograms (kg)

Used for large bars and bulk products:

• 1 kg silver bars (32.15 troy ounces)
• Kilo gold bars
• Bulk silver coins sold by weight

How Metal-Based Pricing Calculates

When you set up metal-based pricing, the price displayed to buyers is calculated in real time:

Display Price = (Current Spot Price per oz × Weight in oz) + Your Premium

Automatic Weight Conversion

If you enter weight in grams or kilograms, CoinDuffle automatically converts to troy ounces for the pricing calculation:

• Grams to troy ounces: Weight in grams ÷ 31.1035
• Kilograms to troy ounces: Weight in kg × 32.1507

Example: A 100g gold bar with a $75 premium:

• 100g ÷ 31.1035 = 3.2151 troy ounces
• If gold spot = $2,350/oz: Price = ($2,350 × 3.2151) + $75 = $7,630.49

Fractional Weights

CoinDuffle handles fractional troy ounce weights accurately:

Configuring Metal Type and Weight on Products

During Product Creation

1. In the product editor, find the Metal Details section
2. Select the Metal Type from the dropdown (Gold, Silver, Platinum, Palladium, or None)
3. Enter the Weight — the actual precious metal content
4. Select the Weight Unit (oz, g, or kg)
5. If using metal-based pricing, these fields are required and feed directly into the price calculation

Important: Use Actual Metal Content

Enter the actual precious metal content, not the total weight of the coin or bar.

Example: The American Gold Eagle has a total weight of 1.0909 oz (it contains copper and silver as alloy metals), but its gold content is exactly 1.0000 troy ounce. Enter 1.0000 oz as the weight.

Example: A $1 face value of pre-1965 US 90% silver coins contains approximately 0.7234 troy ounces of pure silver. Enter 0.7234 oz as the weight.

Common Product Weights Reference

Gold Coins

Silver Coins

Metal Type and Search

When you assign a metal type to your products, they become discoverable through metal-specific filtering:

• Buyers can filter marketplace search by metal type
• Your products appear on metal-specific price pages (Gold, Silver, Platinum, Palladium)
• Products are included in price comparison tools

Accurate metal type assignment ensures your products reach the right buyers.

Products Without Metal Content

Not all products on CoinDuffle contain precious metals. For items like:

• Copper coins and rounds
• Paper currency and banknotes
• Coin albums, holders, and supplies
• Tokens, medals, and exonumia without precious metal content

Select None as the metal type. These products can only use fixed pricing.

Best Practices

• Always verify the metal content before listing — use official mint specifications or trusted references
• Be precise with weights — Buyers who know the market will notice incorrect weights
• Use troy ounces when possible — It's the standard in the industry and the easiest for buyers to understand
• Update weights if you discover an error — Incorrect weights affect metal-based pricing and buyer trust
• Include purity in your description — While CoinDuffle tracks metal content by weight, mentioning the purity (e.g., .999 fine silver) in your description adds clarity