Quality Assurance & Control Flashcards

A customer's appraisal states a diamond color one grade different from its lab report. What is the best response?

Answer: Explain normal grading tolerance and recheck the stone against master stones under standard lighting

A one-grade difference can fall within normal grader variation, and a controlled recheck settles it objectively.

A thermal diamond tester reads "diamond" on a colorless stone. What should be done next?

Answer: Test with an electrical conductivity or moissanite tester and look for doubling

Moissanite conducts heat like diamond, so a second test is needed to rule it out.

Which practice best guards against claims that a stone lost weight during repair?

Answer: Record the weight before and after service on the job ticket

Before-and-after weights give objective proof of the stone's condition.

Before measuring a stone with a millimeter (Leveridge) gauge, what calibration step is needed?

Answer: Close the jaws and confirm the gauge reads zero

Zeroing removes offset errors that would affect every measurement.

Which detail makes a gemstone grading record most auditable?

Answer: Date, grader ID, instruments used, lighting conditions, and photos

Traceable grading conditions let a reviewer reproduce and verify the result later.

A laser inscription does not match the number on the accompanying lab report. What should be done?

Answer: Hold the item, document the mismatch, and verify with the issuing lab before selling

A mismatch may mean a stone switch or paperwork error and must be resolved before sale.

Why is a diamond's fluorescence checked under longwave UV during quality control?

Answer: To document fluorescence that can affect appearance and value

Strong fluorescence can affect appearance in some lighting and is a required grading-report observation.