Banded agate pendant (likely carnelian or brown-and-white chalcedony agate)

The pendant appears to be a polished, cut piece of translucent to opaque orange-brown and cream chalcedony with irregular bands. Quartz has a Mohs hardness of about 7, vitreous to waxy luster, cryptocrystalline structure, no visible cleavage, conchoidal fracture, and a specific gravity near 2.60–2.65. The reddish-orange tones are commonly caused by iron oxides or hydroxides. Exact identification is uncertain from one photograph; it could also be a related carnelian, sardonyx, or jasper-bearing agate.

Agate forms when silica-rich groundwater fills cavities in volcanic rock, especially basalt. Repeated episodes of silica deposition produce the concentric or irregular bands, while later iron-bearing fluids create orange, red, and brown colors. Agates may form during relatively young volcanic episodes or in much older volcanic rocks; the specimen's age cannot be determined from its appearance alone.

Commonly used for pendants, cabochons, beads, carvings, bookends, and decorative objects. Agate is durable and attractive but generally inexpensive unless the pattern, color, locality, or craftsmanship is exceptional.

Agate is not a single mineral but a textural variety of chalcedony containing very fine quartz crystals. Some specimens combine agate with carnelian, jasper, or sardonyx. The metal wire wrapping and drilled hole are human-made, but the polished stone itself is a genuine geological material.

In the field, agate is recognized by waxy or glassy luster, translucency at thin edges, curved/conchoidal fracture, hardness sufficient to scratch ordinary glass, and internal banding or moss-like inclusions. A proper identification would require viewing the edges and reverse, checking translucency, and testing hardness and specific gravity. Common sources include Brazil, Uruguay, Mexico, the United States, Madagascar, India, Botswana, and Germany. The pictured stone may be sold commercially as an orange-banded agate or carnelian agate, but a specific locality cannot be established from the image.