Geometric Shape Appraisal

Rock Crystal Icosahedron

This exquisite item is identified as a Rock Crystal Icosahedron, a particularly rare and valuable object dating from between the end of the 3rd and the end of the 4th century A.D. It is a regular polyhedron, precisely fashioned with 20 faces, each an equilateral triangle. The material is transparent rock crystal, allowing light to beautifully pass through and highlight its multifaceted structure. Each of the 20 triangular faces is meticulously engraved with a symbol from the Greek numerical system, corresponding to numbers 1 through 20. The object appears to be in excellent condition, with no visible chips, cracks, or significant wear. Its surfaces are smooth and well-preserved, indicating good care or stable environmental conditions throughout its existence. The craftsmanship is highly detailed and precise, reflecting advanced geometric and lapidary skills for its period. It was discovered as part of a hoard of valuable objects, including other ancient pieces, within a wooden casket that also contained a bronze lock remnants, suggesting it was part of a preserved and valued collection within a wealthy household ('domus') near the Baths. Its historical context links it to philosophical theories, possibly Neoplatonism, and potentially esoteric or magical properties that are not fully decipherable today. This piece is a testament to ancient mathematical understanding, artistic skill, and the cultural beliefs of the time.