Reference
Glossary
16 terms every lab-grown diamond shopper should know.
- The 4Cs
- The four properties that determine a diamond's grade and price: Cut, Color, Clarity, and Carat weight. Cut has the largest impact on perceived brilliance; carat has the largest impact on price.
- Cut Grade
- A measure of how precisely a diamond's facets reflect light. Grades run Ideal / Excellent → Very Good → Good → Fair → Poor. Cut quality drives the visible sparkle more than any other grade.
- Color Grade
- The D-to-Z scale published by GIA. D is colorless (premium); G–H is near-colorless and visually identical to D in white-gold settings; J–K shows faint warmth that complements yellow-gold settings.
- Clarity Grade
- A measure of internal inclusions and surface blemishes. Runs FL (flawless) → IF → VVS1 → VVS2 → VS1 → VS2 → SI1 → SI2 → I1 → I2 → I3. For lab-grown diamonds, SI1 is almost always eye-clean.
- Carat Weight
- A unit of weight equal to 200 milligrams. Carat weight scales non-linearly with visible size — a 2 ct stone is not twice the face-up area of a 1 ct stone.
- CVD (Chemical Vapor Deposition)
- A lab-growth method that builds a diamond crystal one carbon layer at a time inside a low-pressure plasma reactor. Produces large, high-clarity rough; the two dominant production methods alongside HPHT.
- HPHT (High Pressure, High Temperature)
- A lab-growth method that mimics the natural diamond-forming environment using a metallic flux at extreme pressure. Produces excellent color but is more often used for melee and color-treatment work.
- IGI (International Gemological Institute)
- A diamond-grading laboratory that certifies the majority of lab-grown diamonds sold in the US. IGI lab-grown reports are detailed, photo-documented, and accepted by every reputable retailer.
- GIA (Gemological Institute of America)
- The most prestigious gemological laboratory. Issues both natural and lab-grown diamond reports; for lab-grown stones GIA uses a different report format than for natural diamonds.
- Eye-Clean
- A clarity descriptor meaning no inclusions are visible to the unaided eye at a normal viewing distance of 6–12 inches. For lab-grown diamonds, SI1 stones are eye-clean roughly 95% of the time.
- Concierge Service
- A buying model in which a single expert guides the customer from education through stone selection, mounting design, and post-purchase support — rather than the customer browsing inventory alone.
- Bespoke
- Made to order from individual specifications. A bespoke engagement ring is designed around the wearer's preferences and finger size from raw materials, not assembled from off-the-shelf parts.
- OpenGraph (Open Graph Protocol)
- A meta-tag standard that lets social platforms and answer engines preview a web page with a title, description, and image when shared. Pages without OpenGraph tags share as bare URLs.
- JSON-LD (JavaScript Object Notation for Linked Data)
- A schema.org-based format for declaring structured data on a web page. Search engines and AI answer engines read JSON-LD to understand entities, prices, FAQs, and reviews.
- IndexNow
- A protocol jointly published by Microsoft, Yandex, and others that lets a site notify search engines the instant a page is published or updated, rather than waiting for the next crawl.
- HSTS (HTTP Strict Transport Security)
- An HTTP response header that tells browsers to load the domain over HTTPS only. With the `preload` flag and submission to hstspreload.org, this protection ships in every major browser ahead of the first visit.