Mysterious archaeological objects such as Neolithic stone balls, Roman dodecahedrons and Romano-British cosmetic grinders fascinate both experts and amateurs. From ceremonial implements to everyday objects, their original uses continue to be the subject of speculation and research, reflecting the complexity of ancient life.

Archaeologists are often described as being “amazed” or “stunned” by their discoveries. But in reality, experts have a very good understanding of why most historical objects were created. There are a few exceptions to this rule, however. The following list is a selection of intriguing mystery objects. They are a great example of why excavations in the past continue to fascinate professionals and the public.

1. Neolithic stone balls

Intricately carved stone balls found mostly in Scotland and dating to the late Neolithic period (about 3200-2500 BC) are one such mystery.

More than 425 shells have been found. They are usually the size of cricket balls and are made of a variety of stones. Their surfaces are sometimes shaped like raised circular disks, sometimes with deep incisions defining tubercles and lobes in high relief. The decorations take the form of spirals or concentric shapes reminiscent of those found on ceramics and monumental stones of the period.

Some were found in graves, some in settlements. They are rarely identical, and most occur singly, so they do not appear to be part of a cluster. Some appear to have undergone intensive treatment during their lifetime.

The original use of these stone balls has been the source of much debate since their initial discovery in the 19th century. Many were accidental finds or linger in art collections with little provenance, and are rarely found in an archaeological context. Were these missiles designed to deter predators and pests? Were they weapons of war? Toys? Or perhaps they were measuring scales, household ornaments, mnemonic devices, ball bearings for mobile megaliths, or thread holders? The answer still eludes us.

2. Roman dodecahedrons

These intriguing objects have recently made headlines; Norton Disney’s new discovery in Lincolnshire has sparked much debate about their purpose. Dodecahedrons date back to the Roman period in Britain (AD 43-410). About 130 of them, each finely crafted from a copper alloy, have been found in the northwestern provinces of the former Roman Empire.

There are no known depictions of these objects in ancient art or literature. They don’t fit standard sizes and rarely show signs of use that would indicate their purpose. While armchair experts will tell you that their grandmothers used them to knit gloves, archaeologists are unsure of their purpose.

3. Neolithic chalk drums

Three carved chalk cylinders were discovered in a child’s grave at Faulkton, North Yorkshire, in 1889. The Folkton Chalk Drums have geometric decorations and what appear to be eyes, noses and eyebrows. A fourth, undecorated drum was found at Lavant, West Sussex, in 1993. Another highly decorated example was found at Burton Agnes, East Yorkshire, in 2015.

The Burton Agnes Drum was buried with a chalk ball, a bone needle and the remains of three children, one of whom dated to between 3005 and 2890 BC.

Drum motifs are part of an aesthetic tradition also found on Neolithic stone cannons. Despite their name, chalk drums are unlikely to have been played as musical instruments and do not show the wear and tear associated with the use of percussion instruments.

Some researchers associate their girth with a standard measure of length known as a “longfoot.” Some believe they are references to perishable containers, such as wooden jars or baskets with lids on stone. Others have tried to combine the geometrical markings with astronomical observations. But their presence in the graves of carefully buried children seems to offer a more precise explanation.

4. “Castle rings” of the Bronze Age

The Bronze Age was a period of exceptional goldsmithing. Highly decorative personal jewellery was made of gold leaf and wire. These small half-rings (open) date from the Late Bronze Age (c. 1000–800 BC) and are found in Ireland, Great Britain and parts of France. Often found in matched pairs, they may be plain or have delicate geometric engravings.

Recent interpretations suggest that they may have been nose rings, earrings, or hair ornaments. Neither explanation is satisfactory, as various elements of their design make them difficult or uncomfortable to wear. We need context for graves containing facial ornaments alongside skulls, such as the recent discoveries at Boncuklu Tarla in Turkey.

5. Romano-British cosmetic grinders

Cosmetic grinders are small, two-piece copper alloy kits. One half is a “mortar” (a long, curved, fluted container) and the other is a “pestle” (a pointed rod-shaped or bent into a “rocker”). They often have hanging loops and terminals in the shape of a person or animal.

Waterfowl and goli are common decorative motifs found on other Romano-British vessels such as cups and buckets. Phallic symbolism in some sets has led to an association with fertility. Cosmetic sets are essentially British and are rarely seen in mainland Europe. They date from the Late Iron Age to the Early Roman period (c. 100–200 BC) and are well distributed across the landscape.

Analysis of use and wear showed that these objects were rubbed together during side grinding. Although they worked in a fundamentally different way, they may have replaced the flat marble paddles used in the Roman Empire, using a metal ladle or stone tool to mix the ingredients in a circular motion.

The mystery here is not the function, but the substance from which it was prepared. Offerings included drugs, aphrodisiacs, cosmetics and medicines. The contents of the mortar were never analyzed. This is an opportunity where amateur finders could greatly assist archaeologists by giving up their desire to purge cosmetic solutions and sending them out for study.