Mexican opal from the late 1970s, 4.58 carats. Round cabochon with 10.8 × 10.0mm spread and very shallow 2.0mm depth. Milky white body with light tone and faint remnants of play-of-color.

Extensively crazed — backlit examination reveals a dense network of internal dehydration cracks permeating the entire stone, a common condition in older Mexican opals stored without humidity control over 50+ years. The crazing creates a distinctive mosaic light pattern that some collectors find visually interesting. Surface is intact and polished, but internal structural integrity is compromised.

Not recommended for jewellery that will be worn. Best suited as a gemology study specimen, educational display piece, or curiosity for collectors interested in the effects of aging on gemstone material. An honest example of how time and storage conditions affect hydrated gemstones.