Crystal & mineral guide
Agate
SiO₂ (banded chalcedony)
Banded chalcedony — workhorse of beads, cabochons, and decorative stone trade.
Identify Agate with RockScanAbout Agate
Agate shows concentric or parallel banding from rhythmic silica deposition. Natural earth tones are prized by collectors; vivid commercial colors are often dyed. Widely stocked in Dubai gem souks for beads and carvings. Fortification banding and moss/plume inclusions define specialty varieties.
Agate belongs in a crystal identifier workflow because photo cues — color zoning, crystal habit, and surface luster — combine with measurable traits like Mohs 6.5–7 and specific gravity 2.58–2.64. Use RockScan’s camera to get a first-pass ID, then confirm with the checklist below.
Agate properties
| Mohs hardness | 6.5–7 |
|---|---|
| Crystal system | Trigonal (microcrystalline) |
| Luster | Waxy to vitreous |
| Color | Multicolor banding; often dyed |
| Composition | Banded microcrystalline quartz |
| Formation | Silica gels filling cavities in volcanic rock |
| Occurrence | Brazil, Uruguay, India, Botswana, China |
| Specific gravity | 2.58–2.64 |
| Cleavage | None |
How to identify Agate
- Concentric or parallel banding
- Hardness 7; translucent edges
- Dye concentrates in porous layers — check fractures
Collector notes
- Named for the Achates River in Sicily (Pliny)
- Botswana agate is valued for fine natural banding
Value context: Natural scenic/landscape patterns outprice mass-dyed bead material.
Agate FAQ
How do you identify Agate?
Agate (SiO₂ (banded chalcedony)) is typically recognized by multicolor banding; often dyed color, waxy to vitreous luster, Mohs hardness 6.5–7, and trigonal (microcrystalline) crystal system. RockScan can suggest Agate from a photo and surface these checks on the result card.
What is Agate made of?
Agate composition: Banded microcrystalline quartz. It forms via silica gels filling cavities in volcanic rock and is found in Brazil, Uruguay, India, Botswana, China.
Is Agate valuable?
Natural scenic/landscape patterns outprice mass-dyed bead material.
