Unusual Vintage Large Rectangular Scottish Agate discount Brooch in Silver with Safety Chain

A large rectangular Scottish agate brooch with central banding. Not marked but it has been tested and it isset in a sterling silver mount. There is a silver safety chain. The brooch dates from the 1930's.
The brooch has a 'c' type hook to close with the pin.
The back of the brooch is raw agate, it has not been polished which is unusual.
The brooch is all original and in excellent condition.
Will be carefully packed and sent with Royal Mail signed and tracked service. discount