This stylish, above average size brooch is  7 cm, 2.75 inch long. 

Made from 18ct gold, electronically tested, not marked and fronted in platinum, also tested . 

In the centre is a deep  red ruby. Sparkling and clear, given its age, it is likely to be be synthetic . It is 7mm diameter. 

Rubies were the first man made precious stone , first created at the end of the 1800's and their perfection made them very popular.

Here it is used to give the impression of the heat of the engine.

The brooch has an excellent weight of 5.75 gms

It also has a stay, a small lever that pushes against the pin when closed, as an extra safety precaution.

It is a high quality piece. C1925 -35.