Are these military or campaign medals?

Very few. Against a field of French devotional jewellery, only two British campaign medals appear in the sample: an 1848 Military General Service medal and an 1894 Hong Kong Service medal on its original silk ribbon. The British strand that does recur is award and club medals, golf, football, cricket, tennis, polo, darts, curling, agricultural and masonic, along with watch chain fobs.

Why are so many of them French?

France dominates the origin picture: 132 titles say French and 25 say France, and no other country is named often enough to register in the counts. From the later 19th century French goldsmiths and medal engravers made small gold devotional medals designed to be worn as pendants and given at baptisms, communions and weddings. That production is what fills the category.

What subjects turn up besides the Virgin Mary?

Saints are the next block: St Christopher, St Thérèse, St Joseph, St George and St John the Baptist all appear by name, along with the Sacred Heart, cherubs, First Communion chalices and the Chi Rho. Secular subjects run to zodiac starsigns across at least five signs, love and sentiment medals with French legends, and good luck charms. One-offs occur too: a blood group medical medal, a dog house charm, a deer hunting horn, an EC/CE monogram and a red enamel Maltese cross.

Which decades do most of them come from?

The dated field runs 1850 to 1960, and 184 of the 195 listings carry a clean year, which makes this a well-dated category by jewellery standards. The 1910s are the busiest decade with 55 listings, followed by the 1900s, the 1930s and the 1920s. Roughly three-quarters of dated pieces fall between 1900 and 1939.

Do the medals come with a chain?

Generally not. One title mentions a necklace; the rest are the pendant or charm alone. Boxes and ribbons are equally uncommon in the listings, with a box noted once and a silk ribbon once, on the Hong Kong Service medal.

How often do they come up for sale?

Around 30 come to market in a year on Sellingantiques, and 20 different dealers have listed them, so supply is steady and spread widely rather than sitting with one or two specialists. The French 18k Virgin Mary pendants are the block you meet most often; plique-à-jour and pearl-set pieces are the scarcest, at nine and 17 titles.