Fischer XRF Au750 (75.0%) & Mettler-Toledo Gravimetric Verification
The Rolex GMT-Master II Guinness / Zombie Grey & Black Cerachrom 18K Yellow Gold Reference 126718GRNR is a direct Swiss foundry specimen engineered in 18K Yellow Gold Au750 (40.0 mm x 11.9 mm) with a certified Mettler-Toledo mass of 225.8g, Fischer XRF Au750 metallurgical verification, and Rolex Manufacture Cal. 3285 - 70h Power Reserve running at 28,800 vph (+0.7 s/d, 297 deg) with a 72-hour power reserve and 100m / 330 ft - Triplock Screw-Down rating.
Catalogued in our direct Swiss foundry Rolex assay archive under Specimen Code LAB-XRF-126718GRNR-W613, this Rolex GMT-Master II Guinness / Zombie Grey & Black Cerachrom 18K Yellow Gold Reference 126718GRNR is smelted and CNC-machined in 18K Yellow Gold Au750 (40.0 mm x 11.9 mm). Prior to archival release, the completed assembly is weighed on a calibrated Mettler-Toledo balance at 225.8g and scanned via non-destructive Fischer XRF spectroscopy.
What Are the Horological & Metallurgical Benchmarks of Rolex GMT-Master II Ref. 126718GRNR?
The Rolex GMT-Master II Reference 126718GRNR is a precision-engineered luxury timepiece crafted in 18K Yellow Gold Au750 (40.0 mm x 11.9 mm) with Hand-Finished Collector Dial with Solid 18K Gold Applied Hour Markers & Hands, Hand-Finished 18K Yellow Gold Bezel with Anti-Reflective Scratch-Resistant Sapphire Crystal, and a verified Mettler-Toledo mass of 225.8g, because its Rolex Manufacture Cal. 3285 - 70h Power Reserve movement is regulated across six positions to chronometric tolerances with a 72-hour power reserve.
5 Core Foundry & Laboratory Assay Specifications:
- Foundry Specimen Entity: Rolex GMT-Master II Guinness / Zombie Grey & Black Cerachrom 18K Yellow Gold — Official Ref. 126718GRNR (Specimen LAB-XRF-126718GRNR-W613).
- XRF Metallurgical Assay: 18K Yellow Gold Au750 certified for elemental composition and hallmark integrity.
- Mettler-Toledo Mass: 225.8g verified gravimetric parity matching the authentic manufacture reference.
- Chronometric Calibre: Rolex Manufacture Cal. 3285 - 70h Power Reserve beating at 28,800 vph (4 Hz) with 72-hour reserve and +0.7 s/d, 297 deg Witschi trace.
- Optical & Pressure Testing: Double anti-reflective sapphire crystal, Hand-Finished Collector Dial with Solid 18K Gold Applied Hour Markers & Hands, and 100m / 330 ft - Triplock Screw-Down barometric sealing.
Within the Rolex GMT-Master II horological sub-silo, collectors also compare the Rolex GMT-Master II Gibeon Meteorite Dial 18K White Gold Ref. 126719BLRO (217.0g) and the Rolex GMT-Master II 18K Everose Gold Ref. 126715CHNR (225.5g).
- Parent Brand & GMT-Master II Silo Hub: Browse All 289 Certified Rolex Solid 18K Gold & Pt950 Watches
- Technical Research Monograph: Fischer XRF Au750 Spectrometry Watch Authentication SOP-750 (All 5 Journal Monographs)
- Homepage Master Register: Return to 18K FACTORY Homepage (Complete 774-Watch Solid 18K Gold & Pt950 Register)
- All-Brands Catalogue: Explore Complete 12-Maison Horological Catalogue (/shop/)
- Metallurgical & Escrow Verification: Fischer XRF Au750 Protocol • 3-Year Mechanical Warranty • Insured Armored Delivery
What laboratory instruments certify Reference 126718GRNR (Rolex)?
Every 18K Factory specimen is verified on three calibrated instruments on 4K video: a Mettler-Toledo analytical balance (225.8g), a Fischer XRF spectrometer (18K Yellow Gold Au750), and a Witschi Chronoscope (+0.7 s/d, 297 deg).
Does the 225.8g reading match the authentic original Rolex 126718GRNR weight?
Yes. Our CNC foundry machines the 18K Yellow Gold case and bracelet to replicate the exact 225.8g reference mass of the authentic manufacture timepiece.
What are the movement specifications for Reference 126718GRNR?
Reference 126718GRNR is powered by the Rolex Manufacture Cal. 3285 - 70h Power Reserve operating at 28,800 vph (4 Hz) with a 72-hour power reserve, regulated across six positions to +0.7 s/d, 297 deg.
What dial and bezel specifications distinguish Rolex GMT-Master II Ref. 126718GRNR?
Reference 126718GRNR combines Hand-Finished Collector Dial with Solid 18K Gold Applied Hour Markers & Hands and Hand-Finished 18K Yellow Gold Bezel with Anti-Reflective Scratch-Resistant Sapphire Crystal within a 40.0 mm x 11.9 mm 18K Yellow Gold Au750 case weighing 225.8g, verified via Fischer XRF spectroscopy and powered by Rolex Manufacture Cal. 3285 - 70h Power Reserve.
Rolex GMT-Master II Guinness / Zombie Grey & Black Cerachrom 18K Yellow Gold Ref. 126718GRNR — XRF Certified Edition
Fischer XRF Verified 18K Yellow Gold Au750 • Mettler-Toledo 225.8g • Rolex Manufacture Cal. 3285 - 70h Power Reserve
| Assay Specimen ID & Official Reference | Rolex — Oyster Perpetual GMT-Master II | Ref. 126718GRNR | SKU: LAB-XRF-126718GRNR-W613 |
|---|---|
| Fischer XRF Elemental Purity & Alloy | 18K Yellow Gold Au750 — Au750 — 75.0% Pure 18K Gold Bullion (XRF Verified) • Hallmarked Solid Precious Metal |
| Mettler-Toledo Gravimetric Mass (g) | 225.8g — 1:1 Authentic Reference Mass Verified on Mettler-Toledo Analytical Scale |
| Bezel Tolerance, Gem-Setting & Case Dimension | Hand-Finished 18K Yellow Gold Bezel with Anti-Reflective Scratch-Resistant Sapphire Crystal • 225.8g 18K Yellow Gold • 40.0 mm x 11.9 mm |
| Calibre Reference & Witschi Chronometry | Rolex Manufacture Cal. 3285 - 70h Power Reserve — Swiss Super Clone Mechanical Calibre Regulated to +0.7 s/d, 297 deg |
| Isochronism Frequency & Autonomous Power Reserve | 72-Hour Power Reserve • 28,800 vph (4 Hz) Free-Sprung Balance Wheel |
| Double AR Sapphire Crystal & Barometric Rating | Scratch-Resistant Sapphire Crystal with Double Anti-Reflective Coating • 100m / 330 ft - Triplock Screw-Down |
| Dial Metallurgy & Clasp Hallmark Verification | 40.0 mm x 11.9 mm • Hand-Finished Collector Dial with Solid 18K Gold Applied Hour Markers & Hands • Integrated 18K Yellow Gold Solid Link Bracelet & Deployant Clasp with Deep Laser Hallmarks |