There is a black/purple Diamant 55 cm on ebay now. Maybe it's what you've been looking for. Link: https://www.ebay.com/itm/Vintage-VGC-DIAMANT-featherlight-butted-cr-mo-road-bicycle-frame-55-x-55-cm/293449418078
There is a black/purple Diamant 55 cm on ebay now. Maybe it's what you've been looking for. Link: https://www.ebay.com/itm/Vintage-VGC-DIAMANT-featherlight-butted-cr-mo-road-bicycle-frame-55-x-55-cm/293449418078