gram
gmass · International · Modern
1 g = 0.001 kg.
Converter
mass · Natural pearl trade · Historical-modern specialized
pearl grain
reference-only
- Record
- M558
- Definition quality
- Standardized
- Conversion mode
- reference only
- Calculator
- Reference only
Definition
CIBJO requires natural pearl weight may be expressed in pearl grains, distinct from ordinary/troy grain terminology.
History & use
Pearl trading developed its own mass vocabulary alongside carats and regional units.
Modern use
Modern use is context-dependent and varies by region or measurement system.
Sources & evidence
Source tier — · confidence unknown
- CIBJO Pearl Blue Book (trade convention, text not publicly verifiable) — https://www.cibjo.org/introduction-to-the-blue-books/
- BIPM / NIST Handbook 44 Appendix C — https://www.bipm.org/en/committees/cg/cgpm/4-1907
- Bureau of Standards, U.S. Department of Commerce — https://nvlpubs.nist.gov/nistpubs/Legacy/circ/nbscircular43.pdf
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