Check the seller
The tracker reads public product data from Luciteria Science, Metallium and Smart-Elements. Each product variant keeps its own price, currency, availability and observation date.
Sources & methodology
How Osmium Index collects vendor quotes, records availability and documents public eBay sales. Read weight normalization rules, source coverage and limitations.
Methodology
Every price has
a source and a date.
Use stated metal weight
Price per gram uses an explicit metal weight from the product or variant title. Shipping weights, cube dimensions, approximate weights and weight ranges are excluded. Troy ounces are converted only when the seller identifies them as troy.
Record availability
“In stock,” “sold out,” “usually in stock,” preorder and unknown availability remain distinct. Counts come from public product pages or published variant stock data. A cart availability check is labeled separately as an order limit, expires after 24 hours, and is excluded from listed stock totals. No orders are placed.
Keep the history
Each check is saved as a dated observation. Price and availability changes are compared with the previous successful observation. Failed checks retain visibly stale data. The June 2026 eBay archive remains a separate reference.
What the sales data can—and cannot—tell us
Our volume chart combines minimum documented eBay sold-listing evidence with changes in exact item-specific lifetime counters. A first counter is a baseline, not daily volume. Checks more than 26 hours apart are not allocated to one daily point. Inventory decreases are separate signals, not sales.
Some historical sale years are inferred from source context and weekday; these are flagged per record. Unknown weights and prices stay unknown. A sold listing establishes at least one unit or lot, not every transaction from a multi-unit listing. Accepted offer prices may be undisclosed.
Inspect volume evidence and seller attribution · Download volume observations