Catalog Search Guide
You can search our catalog using different mineral attributes. For example, you can search by color such as green, yellow or purple, or by chemical elements such as uranium, calcium or iron, or by mineral groups such as phosphate, silicate or carbonate. You can also filter by crystal habit like crystal, geode or crystal on matrix, by specimen size such as thumbnail, small, medium or cabinet, and by features such as radioactive or fluorescent minerals.
Chalcedony
Chalcedony is a cryptocrystalline variety of quartz, formed of microscopic fibrous crystals intergrown with minor moganite, giving it a waxy luster and translucent to semi-transparent appearance. Colorless, white, gray, or blue in its purest form, it becomes an entire family of gem varieties once color and pattern enter the picture: banded agate, red carnelian, brown sard, apple-green chrysoprase, dendritic moss agate, blood-spotted heliotrope, black-and-white onyx, and silica-replaced petrified wood all fall under this single mineralogical umbrella.
Typical occurrences are amygdaloidal cavities in basalt and volcanic lava, where silica-rich fluids slowly deposit botryoidal crusts and geode linings. Classic sourcing regions include Uruguay and Brazil for large agate geodes, Namibia and Nevada for fine blue chalcedony, Oregon for its famed thunderegg and carnelian material, and Szklary in Poland alongside Marlborough, Queensland in Australia for chrysoprase. Notable exceptional finds include the iridescent fire agate of the American Southwest, botryoidal carnelian from Somerset County, New Jersey, and the fully silicified logs of Arizona's Petrified Forest.
Prized for hardness (7 on the Mohs scale), durability, and an almost limitless range of colors and banding patterns, chalcedony has been cut, carved, and collected since the Bronze Age. Today collectors seek it for the sheer variety within one species — from museum-grade banded agate slabs to lustrous chrysoprase cabochons and dendritic moss agate specimens showcasing nature's own miniature landscapes.
CHALCEDONY – Shiny Botryoidal Texture from Sant’Antioco, Sardinia, Italy
