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Local Name(s): | Kentish Rag. | ||||||
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Stone Group: | Sedimentary | ||||||
Stone Type: | Limestone | ||||||
Geology: |
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Geological Sub-Divisons: | Lower Greensand Group, Hythe Formation. |
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General Colour Description: | Two layers are important: the Ragstone which is a bluish/grey colour and the Hassock which is a grey colour. |
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Hand Specimen Description: | The ragstone is a hard, coarse grained, sandy limestone comprising rounded, detrital grains of quartz and glauconite, cemented by calcite (85% of the rock is calcium carbonate). It occurs in layers from 10 - 90 cm thick. This is interbedded with layers of hassock, a loamy, calcareous, glauconitic sand (Worssam & Tatton-Brown 1993: 93-4). |
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Petrographic Description: | The proportion of the minerals may differ considerably and the lithology varies considerably along its outcrop. There is every gradation from a sandstone with abundant calcerous cement (mainly of organic origin) to a shelly limestone with scattered sand grains. A predominance of silica indicates a sandstone and in fact the amount of silica of some beds rises to the level where these beds are indeed regarded as sandstones and not limestones. |
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General Comments: | This stone can be mistaken for Reigate stone, however Kentish Rag is not micaceous and is particularly calcareous with rounded rather than amorphous grains of quartz. |
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Stone Identifiers: | Calcareous,  Glauconitic. | ||||||
Reacts dilute to HCl? | Yes |