Overview
ISO 1112:2009 - Horology - Functional and non-functional jewels defines the technical definitions and classification of jewels used in horological movements. The standard specifies what constitutes a functional jewel versus a non-functional jewel, describes the different types and shapes of jewels (bearing holes, cup bearings, surface bearings, jewelled units) and prescribes how the number of functional jewels should be represented on timekeeping instruments and in advertising. ISO 1112:2009 supports consistent product descriptions, fair marketing and reliable quality indicators for watches and clocks.
Key topics and requirements
- Definitions
- Horological jewel: non‑metallic movement components with hardness > HV 1 200.
- Functional jewel: a horological jewel that stabilizes friction and reduces wear and that satisfies Clause 4 criteria.
- Non‑functional jewel: any jewel not meeting the functional criteria.
- Types of functional jewels
- Jewels with a hole serving as radial and/or axial bearings (fixed or movable arbors).
- Jewels without a hole serving axial bearings (fixed or movable).
- Jewels without a hole serving radial bearings (surface bearings).
- Jewels with conical recesses (cup bearings) serving combined radial and axial functions.
- Jewels that contribute to force or movement transmission (e.g., pallet system components).
- Jewelled units (e.g., ball‑bearing assemblies or clutch devices) are counted as a single functional jewel.
- Non‑functional categories
- Ornamental stones, replacement stones, dust covers, oil‑chamber covers, supports for non‑critical moving parts (hour wheel, ratchet), limiters for oscillating masses, date/calendar supports.
- Marking and advertising
- Only the number of functional jewels and functional jewelled units may be cited in sales literature, general advertising and on the instrument itself.
Applications and users
ISO 1112:2009 is practical for:
- Watch and clock manufacturers (design, quality control, product specification).
- Marketing and product teams (accurate jewel count in advertising).
- Importers, customs authorities and regulators using jewel counts for classification or duties.
- Repairers and technical servicing (clarifying function of jewels in movements).
- Component suppliers and assemblers (standardized definitions for parts lists).
Benefits include consistent measurement of movement quality, protection against misleading claims, and harmonized international communication about jewel counts.
Related standards
- ISO 6426‑2 - Horological vocabulary: Part 2 (technical and commercial definitions) - normative reference used by ISO 1112:2009.
- Prepared by ISO/TC 114 (Horology); consult other horology-related ISO standards for complementary specifications.
Keywords: ISO 1112:2009, functional jewels, non-functional jewels, horology, watch jewels, timekeeping instruments, jewel bearings, jewel marking, horological standards.
