chalcedony

chalcedony — noun

1. a type of quartz stone with a soft, waxy shine, often pale blue, milky white, or

1.nounC2
Definition

a type of quartz stone with a soft, waxy shine, often pale blue, milky white, or grey, and slightly see-through; used in jewellery and small carved objects.

Example

Jenna found a smooth blue chalcedony on the beach near her grandmother's house.

common collocation: smooth/polished + chalcedony

The museum displayed Roman seal rings carved from milky chalcedony and red carnelian.

noun: carved chalcedony in historical jewellery

Common collocations
  • smooth chalcedony
  • blue chalcedony
  • polished chalcedony
  • a piece of chalcedony
Synonyms
  • quartz

    broader category — chalcedony is one specific microcrystalline form of quartz

  • agate

    a banded, patterned variety of chalcedony

  • carnelian

    a reddish-orange variety of chalcedony

Usage Note

Almost always uncountable when describing the material; use 'a piece of chalcedony' rather than 'a chalcedony'. Countable only when referring to individual cut stones in a jewellery context.

Common Mistakes

She bought three chalcedonies at the market.
She bought three pieces of chalcedony at the market.
chalcedony is a mass noun for the material; count it with 'piece(s) of' unless naming individual cut stones.

Word family

  • chalcedonic
    adjectiveC2

Synonym discussion

Sense: noun/1

Chalcedony is the umbrella term for fine-grained, waxy-looking forms of quartz; agate and carnelian are both specific kinds of chalcedony. Quartz itself is the wider mineral family — clear rock crystal and amethyst are quartz too, but they form large, glassy crystals rather than the smooth, slightly cloudy mass that chalcedony does. Agate is chalcedony with visible coloured bands or layers, often used for ornaments. Carnelian is the orange-to-red kind, popular in ancient seal rings. In everyday speech, jewellers usually say 'blue chalcedony' or 'grey chalcedony' for plain pieces, and switch to 'agate' or 'carnelian' the moment the pattern or colour is striking enough to deserve its own name.

chalcedony ↗agate ↗carnelianquartz ↗

Common collocations

Nouns

  • chalcedony bead
  • chalcedony pendant
  • chalcedony cabochon

Phrases

  • a piece of chalcedony
  • polished chalcedony

Prepositions

  • carved from chalcedony
  • made of chalcedony

Etymology

GreekLate LatinOld FrenchMiddle EnglishEnglish

Comes from Late Latin 'chalcedonius', borrowed from Greek 'khalkēdōn', a stone mentioned in early Christian texts. The Greek name is thought to refer to Chalcedon, an ancient port city near today's Istanbul, though scholars are not sure whether the stone was actually mined or traded there. English picked the word up in the late 1300s through religious and gemstone literature.