The piece, which is set with enamel and pearls, is expected to fetch up to £5,000 when it goes up for sale in August.
The reverse of the miniature bears a representation of the Royal Arms.
Colin Fraser, specialist on Scottish Silver at auctioneers Lyon & Turnbull, said: “This piece may have had royal connections as it bears the Royal Arms on its reverse. The portrait of the Queen is beautifully executed and of the finest quality, another indication that it might have belonged to an important Scottish family.”
Mary Queen of Scots has been much celebrated and commemorated throughout Scottish history.
Mr Fraser continued “The revival in interest of Scottish history in the reign of King George IV, brought on by the interest in the nation created by Sir Walter Scott’s ‘Waverley Novels’, created many wonderful memorials of Scottish historical figures such as this. Often commissioned by families who had close historical ties to the nation they were now able to be proud to be Scottish and celebrate this only a generation after the upheaval left in the wake of Culloden and the Jacobite uprising.”
Fraser explained: “Although its original commissioner and early history is unknown the fine nature and quality of this piece surely places it within an important Scottish family proud to show their heritage and support for the Stuart Royal line.”
George IV reigned from 29th January 1820 until his own death of his father George III.
In 1822 the visit of King George IV to Scotland was the first by a reigning monarch in nearly two centuries.
The visit increased his popularity in Scotland, turning his subjects away from the rebellious radicalism of the time.
However, it was Sir Walter Scott’s organisation of the visit, with the inclusion of tartan pageantry, that was to have a lasting influence, by elevating the kilt to become part of Scotland’s national identity.