Silver & quartz dagger form, very Scottish Celtic brooch, unusual design, citrine/smokey quartz, vintage 1950s. retailer KI/468

An unusual silver brooch, long and thin and set with 2 cut and faceted quartz stones to form a thistle head, fully hallmarked in Glasgow retailer in 1952 and made by Robert Allison, a well known maker of quality Scottish and Celtic jewellery.
In form it looks like a dagger brooch with 2 thistle leaves rising at an angle, with in between a slight cushion shape quartz to form the body of a thistle head and topped by a shaped quartz to form the top of a thistle head.
Very unusual, never seen this type of double stone before.
The quartz is light brown but in certain light it has an orange cast and could be classed as a cairngorm rather than a pale smokey quartz or dark citrine.
All is good, rollover safety catch, cleaned but not polished.