File:Saddle quern (profile) (FindID 624914).jpg
Original file (1,600 × 1,200 pixels, file size: 756 KB, MIME type: image/jpeg)
Captions
Summary
editsaddle quern (profile) | |||
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Photographer |
Royal Institution of Cornwall, Anna Tyacke, 2014-07-05 15:38:42 |
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Title |
saddle quern (profile) |
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Description |
English: Incomplete coarse greisen saddle quern with a worn concave central reservoir, and one remaining built up edge, through use as a quern or grain mortar. The other edges of the quern have been lost and this may be because the stone was dressed in more recent times in order to re-use it for building material. Similar to other saddle querns found around the county on Bronze Age sites, such as Trethellan, Newquay, where several varied examples were found, the closest in form illustrated in Nowakowski (1991) on pages 144 & 146, Figs.59-60, Nos.92 & 94 from the Middle Bronze Age round house 2001, and a quern derived from a hornfels surface slab with quartz crystals surviving from siltstone, providing 'bite', from the Late Bronze Age contexts at Scarcewater, St Stephens, illustrated in Jones and Taylor (2010) on page 129, Fig.66, No.509.
The greisen probably derives from the nearby outcrop which flanks the granite at Tregonning Hill in Breage. The greisen is coarse with mica flakes of up to 4 mm across and larger quartz grains up to 10 mm across which are particularly prominent where the white mica has eroded out. Greisen is a metasomatically altered granite where the felspar has disappeared and been replaced by white mica, which is also soft. The difference in hardness between the quartz and the mica means that the stone maintains a good grinding surface without becoming smooth. Greisen is also relatively easily shaped, so it was often used for quern production (Dr Roger Taylor pers comm). |
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Depicted place | (County of findspot) Cornwall | ||
Date | BRONZE AGE | ||
Accession number |
FindID: 624914 Old ref: CORN-EC3C8E Filename: stoneimps2014047.JPG |
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Credit line |
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Source |
https://finds.org.uk/database/ajax/download/id/475420 Catalog: https://finds.org.uk/database/images/image/id/475420 Artefact: https://finds.org.uk/database/artefacts/record/id/624914 |
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Permission (Reusing this file) |
Attribution-ShareAlike License | ||
Other versions |
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Licensing
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File history
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Date/Time | Thumbnail | Dimensions | User | Comment | |
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current | 00:39, 21 January 2017 | 1,600 × 1,200 (756 KB) | Fæ (talk | contribs) | Portable Antiquities Scheme, CORN, FindID: 624914, page 1211, batch count 639 |
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Metadata
This file contains additional information such as Exif metadata which may have been added by the digital camera, scanner, or software program used to create or digitize it. If the file has been modified from its original state, some details such as the timestamp may not fully reflect those of the original file. The timestamp is only as accurate as the clock in the camera, and it may be completely wrong.
Camera manufacturer | NIKON |
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Camera model | E4500 |
Exposure time | 1/137 sec (0.0072992700729927) |
F-number | f/5.5 |
ISO speed rating | 100 |
Date and time of data generation | 14:59, 5 July 2014 |
Lens focal length | 8.7 mm |
Orientation | Normal |
Horizontal resolution | 300 dpi |
Vertical resolution | 300 dpi |
Software used | Microsoft Windows Photo Viewer 6.1.7600.16385 |
File change date and time | 15:31, 5 July 2014 |
Y and C positioning | Co-sited |
Exposure Program | Normal program |
Exif version | 2.2 |
Date and time of digitizing | 14:59, 5 July 2014 |
Meaning of each component |
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Image compression mode | 4 |
APEX exposure bias | 0 |
Maximum land aperture | 2.8 APEX (f/2.64) |
Metering mode | Center weighted average |
Light source | Tungsten (incandescent light) |
Flash | Flash did not fire, compulsory flash suppression |
Supported Flashpix version | 1 |
Color space | sRGB |
File source | Digital still camera |
Scene type | A directly photographed image |
Custom image processing | Normal process |
Exposure mode | Auto exposure |
White balance | Manual white balance |
Digital zoom ratio | 0 |
Focal length in 35 mm film | 42 mm |
Scene capture type | Standard |
Scene control | None |
Contrast | Normal |
Saturation | Normal |
Sharpness | Normal |
Subject distance range | Unknown |