Glossary
Lead-glass filling
Heavily fractured rubies may have their fissures filled with lead-bearing glass. The stone then looks clearer but becomes more delicate – for example to heat or acids at the jeweller’s bench. Laboratories always disclose this treatment explicitly. Such stones form a separate, much lower-priced market segment and are not comparable with untreated or merely heated rubies.
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Updated 2026-10-06