What is GDTC?
GDTC (Gemological and Diamonds Testing Center) is an independent laboratory that evaluates and documents the materials and craftsmanship of fine jewelry. A GDTC certificate is an unbiased reference describing the piece’s metal, stones, and key quality attributes.
Why certification matters
- Authenticity: Confirms that metals and gemstones are genuine and as described.
- Transparency: Provides a detailed record of a piece’s composition and grading.
- Confidence: Supports valuation for insurance and future resale.
How to read your report
- Report Number: A unique ID for verification. Keep a photo or copy with your records.
- Metal Section: Lists the alloy (e.g., 14K rose gold) and hallmarking where applicable.
- Gemstone Section: For each stone type, you’ll see measurements, weight, cut, color, and clarity or transparency.
- Comments: Notes on treatments, setting integrity, and recommendations for care.
- Photograph/Diagram: Some reports include images or plot diagrams to reference inclusions and setting layout.
Common terms explained
- Carat (ct): The weight of a gemstone. Total carat weight (tcw) sums all stones of the same type.
- Clarity: Visibility of internal inclusions and external blemishes (for diamonds and some gems).
- Color Grade: For diamonds, ranges from D (colorless) to Z (light color); for topaz, describes hue and saturation.
- Cut: The proportions and finish that affect brilliance and fire.
- Treatments: Processes such as heat or irradiation (commonly disclosed for blue topaz) that enhance color.
Verifying authenticity
Most certificates include a QR code or online lookup. Match the report number to your piece. If the item was resized or altered, consult a jeweler—significant changes can affect the report’s applicability.
Care and long‑term value
Certification and proper care go hand in hand. Store your certificate with your insurance files and keep digital backups. Follow cleaning guidance suitable for your stones and metal, and schedule periodic inspections to maintain both beauty and value.
Frequently asked questions
Is GDTC the same as GIA?
Both are independent laboratories. Naming conventions and grading scopes may differ, but the goal is similar: objective documentation. Your Rose Sky Jewels purchase includes certification appropriate to the piece.
Do all pieces come with a certificate?
High‑value items and those with featured gemstones typically include certificates. For other pieces, we provide detailed material descriptions and can arrange certification upon request.
Will resizing affect my certificate?
Minor adjustments usually won’t, but major alterations can. Keep documentation of any changes made by a professional jeweler.