page_title: Roman cement
hierarchical_section_title: Roman cement
caption_attribution_description: English: The South Door of Lichfield Cathedral Above the ornate doorway stand seven figures carved in Roman cement. Christ stands in the centre. On the right are Saint Chad, Saint James and John the Baptist. On the left are Saint Peter, Saint John and the Virgin Mary.
context_page_description: Roman cement is a substance developed by James Parker in the 1780s, being patented in 1796.
  The name is misleading as it is nothing like any material used by the Romans, but was a "natural cement" made by burning septaria – nodules that are found in certain clay deposits, and that contain both clay minerals and calcium carbonate. The burnt nodules were ground to a fine powder. This product, made into a mortar with sand, set in 5–15 minutes. The success of Roman cement led other manufacturers to develop rival products by burning artificial mixtures of clay and chalk.
context_section_description: Roman cement is a substance developed by James Parker in the 1780s, being patented in 1796.
  The name is misleading as it is nothing like any material used by the Romans, but was a "natural cement" made by burning septaria – nodules that are found in certain clay deposits, and that contain both clay minerals and calcium carbonate. The burnt nodules were ground to a fine powder. This product, made into a mortar with sand, set in 5–15 minutes. The success of Roman cement led other manufacturers to develop rival products by burning artificial mixtures of clay and chalk.
caption: Above the ornate south doorway of Lichfield Cathedral stand seven figures carved in Roman cement.
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