What Xene certifies, and how.

The numerical assessment of a collectible's preservation under a published scale. Xene grades coins on the 70-point Sheldon scale, banknotes on a 70-point paper-money scale, trading cards on a 10-point scale with sub-grades, and stamps under a centering-and-condition rubric. Each grade is the consensus of two senior specialists working blind, reconciled by a finaliser.

The determination that an item is genuine — that it is what it purports to be, and not a counterfeit, reproduction, or substitution. Xene authenticates through comparative microscopy at up to 200×, raking and ultraviolet light, XRF metallurgical spectroscopy where appropriate, and provenance review. Two senior specialists must independently authenticate before grading begins.

The sealing of a graded item into an inert, UV-stable archival holder, machined to the item's dimensions and sonically welded. Opening the holder is mechanically destructive and immediately visible. Each Xene holder embeds an NFC tag and laser-engraved certificate number tied to a public registry entry.

A transferable, indefinite warranty of authenticity attached to every Xene certificate, underwritten by Lloyd's of London under policy LM/2024/8841. Should an item be proven inauthentic, the bearer is compensated at prevailing market value, capped at the lesser of £5m per item or the auction value at date of claim.

Cover for items in transit and on Xene's premises. Blanket Hiscox cover to £5m per parcel from the moment the appointed courier collects, and a Class III Eurograde vault at Hatton Garden with twin-key access, motion and seismic sensors. Distinct from — and additional to — the lifetime guarantee.

The reconstruction of an item's ownership and exhibition history before grading begins. Xene consults hallmark registers, auction catalogues, dealer archives, museum records, and the Art Loss Register where appropriate. Items of contested provenance are declined.

The permanent record of every Xene certificate, accessible by NFC tag, QR code or certificate-number lookup. Hosted on segregated UK infrastructure with monthly notarised cold-archive snapshots. Running continuously since 2014.

The published grading rubrics Xene applies, by discipline. Each standard is a publicly documented methodology, comparable to the conventions used by PCGS, NGC, PMG, PSA, BGS, CGC and the RPSL — but issued, signed and audited by Xene itself.

Xene neither buys, sells nor brokers any item it grades. No specialist may hold a beneficial interest in any item submitted to the firm. The firm declines items of contested provenance and does not provide expert-witness services where it has a prior or concurrent commercial relationship with either party.