BGS Rock Classification Scheme
Agate - A type of chert consisting of translucent cryptocrystalline quartz. This is a variegated chalcedony, commonly mixed or alternating with opal and characterised by banded colours. British Geological Survey Research Report RR/99/03, section 8.2 and fig. 12.
| Code | AGATE |
|---|---|
| Description | Agate - A type of chert consisting of translucent cryptocrystalline quartz. This is a variegated chalcedony, commonly mixed or alternating with opal and characterised by banded colours. British Geological Survey Research Report RR/99/03, section 8.2 and fig. 12. |
| Qualifiers | No qualifiers currently exist. |
| Definition | Non-clastic sedimentary rocks with >50% silica of biogenic or chemical origin, porosity <10% hard, dense with vitreous lustre. Translucent cryptocrystalline <0.004mm quartz, colour banded, commonly opal present. |
| Linked data | http://data.bgs.ac.uk/id/EarthMaterialClass/RockName/AGATE |
CAVEAT
"Thumbnail" definitions attached to some of the table entries are an interim attempt to provide simple short descriptions of the "unqualified" rock types presented within the BGS Rock Classification Scheme. Every effort has been made to ensure accuracy and consistency but minor contradictions or omissions might be present. The BGS welcomes any feedback pointing out such minor imperfections and/or providing constructive comment and suggestions for improvement of the definitions. In the first instance such feedback should be directed to Dr Tim McCormick.