BGS Rock Classification Scheme
Opaline-porcellanite - A type of porcellanite in which the silica includes amorphous silica (opal-A), opal CT, low-cristobalite and tridymite. British Geological Survey Research Report RR/99/03, section 8.2 and fig. 12.
| Code | OPORCE |
|---|---|
| Description | Opaline-porcellanite - A type of porcellanite in which the silica includes amorphous silica (opal-A), opal CT, low-cristobalite and tridymite. British Geological Survey Research Report RR/99/03, section 8.2 and fig. 12. |
| Qualifiers | No qualifiers currently exist. |
| Definition | Non-clastic siliceous sedimentary rocks with >50% silica of biogenic or chemical origin, porosity 15 to 30%. Texture, lustre & conchoidal fracture of porcelain. Silica, amorphous (opal-A), opal CT, low-cristobalite & tridymite. Dominantly <0.004mm |
| Linked data | http://data.bgs.ac.uk/id/EarthMaterialClass/RockName/OPORCE |
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.