Consistent protocols, independent oversight and international accreditation stand behind every JTR report.
JTR Gemology Grading Laboratory operates under internationally recognised procedures and is accredited by the International Accreditation Service (IAS), confirming the competence and impartiality of our grading.
IAS Accredited laboratory
ISO - 17025 Testing competence
IDC Grading rules
Global Recognised worldwide
Graders work without knowledge of commercial value or ownership, removing bias from the result.
Standardised lighting, calibrated instruments and documented methods on every stone.
Laser inscription and a digital record link each stone to its report for life.
JTR’s grading procedures follow the rule book of the International Diamond Council (IDC), founded in 1975 by the WFBD and IDMA. In 2017 the IDC and CIBJO diamond books were brought together under a single framework, giving the global diamond trade one common language.
JTR holds ISO/IEC 17025 accreditation. It confirms, through an independent body, the technical competence of the laboratory, the reliability of its measurement results and the effectiveness of its quality management system — the highest recognised competence standard for testing and calibration laboratories worldwide.
ISO 24016:2020 defines the terminology and methods used in diamond grading, while ISO 18323 sets the product description and labelling rules that protect consumer confidence in the jewellery industry. Together they govern both what a report says and how it says it.
For you, compliance is a concrete assurance: every JTR report is produced by internationally accepted methods, so results are repeatable, comparable and auditable. Standards protect the value of your diamond.