File:Brooch - hinged two-piece Colchester derivative (Dolphin) brooch (FindID 963487).jpg

English: An incomplete copper alloy hinged two-piece Colchester derivative (Dolphin) brooch of Roman date (43-150AD). The wings are complete and cylindrical. A longitudinal hole is present to take the axis bar. At the centre of the wings, on the reverse face is a vertical slit. The pin is lost however the copper alloy axis bar is present and complete. The bow head of the brooch is relatively flat although this may be due to distortion in the ground. More commonly these bows are hump-like, and slightly angular. The bow is angular in cross section being almost triangular with a prominent cast central ridge running along the apex of the bow - this is flanked by two cast grooves running along but respecting the external long edges. The bow tapers along its length to an abraded rounded point / foot. The catch plate on the reverse face of the bow is complete (although abraded). It expands from a central rib which emanates from the lower foot of the reverse of the bow. The outer edge of the catchplate is lost but a pin rest is likely to have been created by the external edge being rolled to create a U shaped catch. Apart from the previously described longitudinal grooves theer is no other applied, cast, or incised decoration present. The brooch is a dark mid green colour with an even polished but slightly abraded patina. This abrasion is probably caused by movement in the plough soil and has resulted in damage around the extremities of the brooch. The brooch has also been heavily distorted by movement flattening it. Similar hinged dolphin brooches can be seen in Richard Hattatt's Visual Guide to Ancient brooches pp 299 fig; 158: reference 20 and 21. Closer parallels can be seen in Crummy Colchester Report pp11-13 reference 58-60, and Bayley and Butcher "Roman brooches in Britain" p90 figure 70. A discussion in the Bayley volume on pin attachment can be seen on pp32-34, the style of pin attachment is classified as type 20:11

The brooch measures 44.8mm length, 16.9mm width across the wings, 7.5mm width across the bow and is 3.2mm thick also across the bow. It weighs 6.39 grams.