Four early 20th century diamond-set brooches

Four early 20th century diamond-set brooches
Comprising: a blue enamel circlet brooch with diamond-set circlet side detail, 3.5cm wide; an octagonal brooch with seed pearl border, one deficient, and a single old brilliant-cut diamond collet, 2.3cm wide; an oval brooch set with eight old brilliant-cut diamond collets in a diamond-set pierced surround with calibre-cut emerald details, 3.8cm wide; and a diamond-set pierced circlet brooch, 4.2cm wide