Chalcedony
| Colour | Blue, White, Gray |
|---|---|
| Mohs hardness | 6–7 |
| Lustre | Waxy, vitreous, dull, greasy, silky |
| Streak | White |
| Crystal system | Trigonal (quartz) or monoclinic (moganite) |
| Transparency | Translucent |
| Cleavage | Absent |
| Fracture | Uneven, splintery, conchoidal |
| Chemical formula | (silica) |
| Specific gravity | 2.59–2.61 |
What is Chalcedony?
Chalcedony is an aggregate of cryptocrystalline or microcrystalline silica, or in simpler terms, a mass of individual silica crystals that are too small to be seen without magnification. It is composed primarily of quartz, with minor amounts of intergrown moganite. These are both silica minerals with a chemical composition of SiO2, but they differ in that quartz has a more symmetrical crystal structure (trigonal) than moganite (monoclinic). Mineralogically speaking, the quartz and moganite crystals in chalcedony must grow in parallel chains, called "fibers." However, the term chalcedony may mo
How to identify Chalcedony
- Lustre: Waxy, vitreous, dull, greasy, silky.
- Hardness: Mohs 6–7 — about as hard as a steel knife.
- Streak: White.
- Habit: Trigonal (quartz) or monoclinic (moganite) crystal system.
Chalcedony value
Based on 100 recent eBay sold listings, a raw / cluster Chalcedony typically sells for $7–$22. After eBay fees a seller nets roughly $9 on a median piece.
| Recently sold | Weight | Sold | Date |
|---|---|---|---|
| Red & Yellow Chalcedony Jasper Agate, Rough Lapidary Rock, 6 LBS, 8 OZ, #503 | 2722 g | $7 | 2026-06-21 |
| 2.57LB Natural Grape Agate Chalcedony Crystal Mineral Sample | 1166 g | $11 | 2026-06-21 |
| Natural Chrome Chalcedony 925 Sterling Silver Ring s.7 Jewelry R-1253 | — | $22 | 2026-06-21 |
| 925 Sterling Silver Natural Onyx Gemstone Women Ring Vintage Handmade Jewelry | — | $16 | 2026-06-20 |
| 37g Beautiful Natural Purple Grape Agate Chalcedony Crystal Mineral Specimen | 37 g | $10 | 2026-06-20 |
| 925 Sterling Silver Signet Men's Ring with Natural Chalcedony Gemstone | — | $42 | 2026-06-21 |
Typical recently-sold prices, 2026-06. Condition, size and quality vary widely, so this is an estimate, not an appraisal. See current sold listings on eBay ↗. Full value guide · how we work this out.
