AllMineralsRock
Chalcedony Vs. Quartz
Chalcedony is a very popular gemstone composed of silicon dioxide.[1] Quartz is also a very popular gemstone and its chemical composition is also silicon dioxide.[2]
Quick Facts on Differences of Chalcedony and Quartz
For a quick recap of the differences chalcedony and quartz:- While both chalcedony and quartz can be vitreous or waxy, in terms of luster, chalcedony can be dull and quartz can be greasy.
- While both chalcedony and quartz can be commonly red, quartz is often yellow.
Quick Facts on Similarities of Chalcedony and Quartz
The similarities of chalcedony and quartz include:- Chalcedony and quartz both can be opaque, translucent or transparent.
- In terms of crystallography, chalcedony and quartz both can be hexagonal or trigonal.
- For chemical formulas, chalcedony and quartz both are SiO2.
- Chalcedony and quartz both streak white.
- Chalcedony's rarity is similar to quartz.
- Chalcedony's hardness is similar to quartz - they both are 7 on the Moh's scale.
- Chalcedony's specific gravity overlaps with quartz - chalcedony ranges from 2.55 to 2.91 and quartz ranges from 2.651 to 2.91.
Summary of Chalcedony
Chalcedony is a mineral that is widely used in jewelry making, carvings, and decorative objects. It is a member of the quartz family and is composed of microscopic crystals of quartz that are arranged in a fibrous or microcrystalline structure. The mineral is typically translucent or opaque and can come in a range of colors, including white, gray, blue, brown, and red. Chalcedony is often found in association with other minerals such as agate, jasper, and onyx.Summary of Quartz
Quartz is a mineral that is composed of silicon and oxygen atoms arranged in a continuous framework of SiO4 silicon-oxygen tetrahedra. It is one of the most abundant minerals found in the Earth's crust. Quartz can be found in a variety of colors such as white, pink, purple, brown, gray, and black. It is also known for its unique crystal structure, which is hexagonal in shape, and its hardness, which is 7 on the Mohs scale.Table Comparison of Chalcedony vs Quartz
| Chalcedony (src) | Quartz (src) | |
|---|---|---|
| Transparency | transparent, translucent, opaque | transparent, translucent, opaque |
| Chemical Formula | SiO2 | SiO2 |
| Chemical Composition | silicon dioxide | silicon dioxide |
| Specific Gravity | 2.55, 2.91 | 2.651, 2.91 |
| Hardness | 7 | 7 |
| Streak | white | white |
| Crystallography | hexagonal, trigonal | hexagonal, trigonal |
| Refractive Index | 1.54, 1.553 | 1.544, 1.553 |
| Hydrous | No | No |
| Colors | common: red sometimes: blue, gray, pink, black, brown, green, white, orange, purple, yellow, band, multicolor |
common: red, yellow sometimes: blue, gray, pink, black, brown, green, white, orange, purple, violet, colorless, multicolor |
| Category | quartz | silicate |
| Fracture | conchoidal | conchoidal, uneven |