Fischer XRF Au750 (75.0%) & Mettler-Toledo Gravimetric Verification
The Rolex Day-Date 36 18K Yellow Gold Reference 128238 is a direct Swiss foundry specimen engineered in 18K Yellow Gold Au750 (36.0 mm x 12.0 mm) with a certified Mettler-Toledo mass of 183.3g, Fischer XRF Au750 metallurgical verification, and Rolex Manufacture Cal. 3255 - 70h Power Reserve running at 28,800 vph (+0.8 s/d, 301 deg) with a 72-hour power reserve and 100m / 330 ft - Twinlock Screw-Down rating.
Catalogued in our direct Swiss foundry Rolex assay archive under Specimen Code LAB-XRF-128238-W689, this Rolex Day-Date 36 18K Yellow Gold Reference 128238 is smelted and CNC-machined in 18K Yellow Gold Au750 (36.0 mm x 12.0 mm). Prior to archival release, the completed assembly is weighed on a calibrated Mettler-Toledo balance at 183.3g and scanned via non-destructive Fischer XRF spectroscopy.
What Are the Horological & Metallurgical Benchmarks of Rolex Day-Date President Ref. 128238?
The Rolex Day-Date President Reference 128238 is a precision-engineered luxury timepiece crafted in 18K Yellow Gold Au750 (36.0 mm x 12.0 mm) with Hand-Finished Collector Dial with Solid 18K Gold Applied Hour Markers & Hands, Signature Rolex Fluted 18K Yellow Gold Bezel with Anti-Reflective Scratch-Resistant Sapphire Crystal, and a verified Mettler-Toledo mass of 183.3g, because its Rolex Manufacture Cal. 3255 - 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 Day-Date 36 18K Yellow Gold — Official Ref. 128238 (Specimen LAB-XRF-128238-W689).
- XRF Metallurgical Assay: 18K Yellow Gold Au750 certified for elemental composition and hallmark integrity.
- Mettler-Toledo Mass: 183.3g verified gravimetric parity matching the authentic manufacture reference.
- Chronometric Calibre: Rolex Manufacture Cal. 3255 - 70h Power Reserve beating at 28,800 vph (4 Hz) with 72-hour reserve and +0.8 s/d, 301 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 - Twinlock Screw-Down barometric sealing.
Within the Rolex Day-Date President horological sub-silo, collectors also compare the Rolex Day-Date 40 Graduated Blue Ombre Dial 18K White Gold Ref. 228239 (210.6g) and the Rolex Day-Date 40 Graduated Ombre Sunray Dial 18K Everose Gold Ref. 228235 (210.8g).
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- Technical Research Monograph: Fischer XRF Au750 Spectrometry Watch Authentication SOP-750 (All 5 Journal Monographs)
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- 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 128238 (Rolex)?
Every 18K Factory specimen is verified on three calibrated instruments on 4K video: a Mettler-Toledo analytical balance (183.3g), a Fischer XRF spectrometer (18K Yellow Gold Au750), and a Witschi Chronoscope (+0.8 s/d, 301 deg).
Does the 183.3g reading match the authentic original Rolex 128238 weight?
Yes. Our CNC foundry machines the 18K Yellow Gold case and bracelet to replicate the exact 183.3g reference mass of the authentic manufacture timepiece.
What are the movement specifications for Reference 128238?
Reference 128238 is powered by the Rolex Manufacture Cal. 3255 - 70h Power Reserve operating at 28,800 vph (4 Hz) with a 72-hour power reserve, regulated across six positions to +0.8 s/d, 301 deg.
What dial and bezel specifications distinguish Rolex Day-Date President Ref. 128238?
Reference 128238 combines Hand-Finished Collector Dial with Solid 18K Gold Applied Hour Markers & Hands and Signature Rolex Fluted 18K Yellow Gold Bezel with Anti-Reflective Scratch-Resistant Sapphire Crystal within a 36.0 mm x 12.0 mm 18K Yellow Gold Au750 case weighing 183.3g, verified via Fischer XRF spectroscopy and powered by Rolex Manufacture Cal. 3255 - 70h Power Reserve.
Rolex Day-Date 36 18K Yellow Gold Ref. 128238 — XRF Certified Edition
Fischer XRF Verified 18K Yellow Gold Au750 • Mettler-Toledo 183.3g • Rolex Manufacture Cal. 3255 - 70h Power Reserve
| Assay Specimen ID & Official Reference | Rolex — Oyster Perpetual Day-Date 36 | Ref. 128238 | SKU: LAB-XRF-128238-W689 |
|---|---|
| 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) | 183.3g — 1:1 Authentic Reference Mass Verified on Mettler-Toledo Analytical Scale |
| Bezel Tolerance, Gem-Setting & Case Dimension | Signature Rolex Fluted 18K Yellow Gold Bezel with Anti-Reflective Scratch-Resistant Sapphire Crystal • 183.3g 18K Yellow Gold • 36.0 mm x 12.0 mm |
| Calibre Reference & Witschi Chronometry | Rolex Manufacture Cal. 3255 - 70h Power Reserve — Swiss Super Clone Mechanical Calibre Regulated to +0.8 s/d, 301 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 - Twinlock Screw-Down |
| Dial Metallurgy & Clasp Hallmark Verification | 36.0 mm x 12.0 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 |