The second was white, 5ft 8in, stocky, and was wearing a black top of the same style, jeans and white trainers.
Detective Inspector Laura Thomson said: "At this time, it has still to be established exactly what was stolen and the value of the jewellery but it is believed to be a considerable amount.
"I would urge anyone who saw anyone behaving in a suspicious manner at The Fort around 11am this morning or saw the suspects enter or leave the premises to come forward.
"I am also anxious to speak to anyone who saw the Volkswagen Golf car driving from the scene."