gemstone

Chalcedony (Dyed Agate and Citrine-style Quartz)

Silicon Dioxide (SiO2)

Hardness: 6.5-7 on Mohs scale. Luster: Vitreous to waxy. Color: Cobalt blue (dyed), honey yellow, and milky white. Structure: Cryptocrystalline or hexagonal crystal systems. Cleavage: None.

Hardness: 6
Color: Cobalt blue (dyed), honey yellow, and milky white
Luster: Vitreous to waxy

Identified July 19, 2026More gemstone →

Explore Chalcedony (Dyed Agate and Citrine-style Quartz) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 6.5-7 on Mohs scale. Luster: Vitreous to waxy. Color: Cobalt blue (dyed), honey yellow, and milky white. Structure: Cryptocrystalline or hexagonal crystal systems. Cleavage: None.

Formation & geological history

Formed through the deposition of silica from groundwater in cavities of igneous and sedimentary rocks. The blue beads are likely dyed chalcedony or agate, while the lighter beads are quartz variants.

Uses & applications

Primarily used in jewelry (beads, bracelets, necklaces) and decorative ornamental crafts.

Geological facts

The intense cobalt blue color in these beads is achieved through a dyeing process, as natural blue agate is typically much paler or more grayish. Quartz and its varieties are the most abundant minerals in the Earth's crust.

Field identification & locations

Identify by its hardness (it can scratch glass) and waxy luster on fractured surfaces. Common in regions with volcanic activity or hydrothermal vents.

Other gemstone specimens

See all

Diamond and Gold Jewelry

Carbon (Diamond) / Au (Gold)

gemstone

Ammolite

Ammolite (Biogenic Aragonite with trace elements; fossils of Placenticeras meeki and Placenticeras intercalare)

mineral

Cubic Zirconia (simulant) or Diamond

ZrO2 (Cubic Zirconia) or C (Diamond)

gemstone

Red Jasper

Silicon Dioxide (SiO2) with Hematite inclusions

sedimentary

Cubic Zirconia (or possibly Diamond)

Zirconium dioxide (or Carbon)

gemstone

Faceted Gemstone

Unknown transparent mineral, possibly Diamond (C), Cubic Zirconia (ZrO2), Quartz (SiO2), or Glass

gemstone