File:Early-medieval brooch, Keystone-garnet brooch (FindID 621421).jpg

English: An incomplete copper alloy 'keystone-garnet' disc brooch of Avent's (1975) Class 2.1, dating to the early Early-medieval (Anglo-Saxon) period. The brooch has a central setting of an unidentified white substance, possibly a paste or shell or bone, with a light red (pinkish) glass or possibly a garnet set in the middle within a gold cradle; the gold can be seen around the outer edge of the red insert and also beneath it, where the gold is meshed which would have aided in reflecting light back out through the insert, making it shine brighter. Around the central setting is a circular panel that contains alternating circles and triangles, three of each, which may have also held decorative inserts although no trace of these now survives. There may be decoration between the stone settings however encrustations obscures this from view. A thin border separates the panel from a slightly raised but plain outer band. On the reverse of the brooch is the remains of the catchplate and pin lug; iron concretion suggests an iron pin, which is now missing. A gilded copper keystone-garnet brooch with four alternating circles and triangles was found in the grave of a female child at Butler's Field, Lechlade (Boyle et al 1998:60). Keystone-garnet brooches date to the six century AD.

Several examples with a similar decorative style (of a central circle and three wedge-shaped projections) are illustrated in Macgregor & Bolick (1993:70-73) although the majority are silver gilt. Where it survives, the central circular cell in these examples is often filled with a white material (possibly shell or coral), with the wedges encasing garnets. These were obviously expensive brooches and it is not surprising that cheaper versions were made. Other copper alloy examples recorded on the PAS database do retain some of their settings (see, for example, HAMP-9B6151). The materials are glass (usually red) or possibly poor quality garnets with unidentified white material in the centre. One copper alloy example illustrated in Macgregor & Bolick (ibid. p76 no.6.23) exhibits yellow glass settings in three tear-shaped cells.

This brooch is a copy of those made in Kent in the second quarter of the 6th century. Two others recorded from Wiltshire and Hampshire have been dated to c.530-570. For other examples recorded on this database please see CAM-274762, HAMP-9B6151, WILT-F561A1, WILT-6F2B84, BUC-4B3412 and BERK-6DD561. See also IOW-A33D42, IOW-C938C0 and KENT4837.