Keep weight and content separate
Theoretical fine-gold fractions are 18/24, or 75%, and 22/24, or about 91.67%. Equal net alloy weights therefore do not contain equal theoretical amounts of gold. These fractions describe content; they are not purity tests or prices.
Ask what the quotation covers
For either item, identify stone weight, net metal weight, the purity-specific rate and all additional charges. A design with a lower gold fraction is not automatically cheaper overall. Design, fabrication and the non-metal components can change the total substantially.
Compare written resale terms
Ask how the buyer assesses purity, how stones are treated and which deductions apply. Enter the proposed buyback rate in the old-gold estimator, not the rate for newly purchased jewellery. Use the purity converter to understand theoretical content separately from the invoice calculation.