AllMineralsRock
Aragonite Vs. Hemimorphite
Aragonite is a popular mineral composed of calcium carbonate.[1] Hemimorphite is also a popular mineral and its chemical composition is zinc silicate.[2]
Quick Facts on Differences of Aragonite and Hemimorphite
For a quick recap of the differences aragonite and hemimorphite:- While both aragonite and hemimorphite can be orthorhombic, in terms of crystallography, aragonite can be hexagonal.
- For chemical formulas, aragonite is CaCO3 while hemimorphite is Zn4Si2O7(OH)2· H2O.
- While both aragonite and hemimorphite can be dull or vitreous, in terms of luster, aragonite can be resinous and hemimorphite can be adamantine, silky or waxy.
- Aragonite streaks white while hemimorphite streaks colorless.
- Aragonite can be commonly green while hemimorphite can be commonly blue, brown or yellow.
-
Aragonite's hardness is lower than hemimorphite - aragonite ranges from 3.5 to 4 and hemimorphite ranges from 4.5 to 5 on the Moh's scale.
- Aragonite can be scratched by the average knife blade (4.5) while hemimorphite can not be.
- Aragonite's specific gravity is lower than hemimorphite - aragonite ranges from 2.93 to 2.947 and hemimorphite ranges from 3.4 to 3.5.
Quick Facts on Similarities of Aragonite and Hemimorphite
The similarities of aragonite and hemimorphite include:- Aragonite and hemimorphite both can be opaque, translucent or transparent.
- Aragonite's rarity is similar to hemimorphite.
Summary of Aragonite
Aragonite is a mineral that is commonly found in sedimentary rocks such as limestone, dolomite, and marble. It is a polymorph of calcium carbonate, which means that it has the same chemical formula as calcite but a different crystal structure. Aragonite is named after the Aragon region in Spain where it was first discovered.Summary of Hemimorphite
Hemimorphite is a zinc silicate mineral that is often found in the oxidation zone of zinc ore deposits. It is a relatively rare mineral that can be identified by its unique crystal habit. Hemimorphite crystals are typically tabular and can display a range of colors including white, blue, green, and yellow. The mineral often occurs in botryoidal or stalactitic forms and can also be found as crusts or coatings on other minerals.Table Comparison of Aragonite vs Hemimorphite
| Aragonite (src) | Hemimorphite (src) | |
|---|---|---|
| Transparency | transparent, translucent, opaque | transparent, translucent, opaque |
| Chemical Formula | CaCO3 | Zn4Si2O7(OH)2· H2O |
| Chemical Composition | calcium carbonate | zinc silicate |
| Specific Gravity | 2.93, 2.947, 2.95, 3 | 3.4, 3.5 |
| Hardness | 3.5, 4 | 4.5, 5 |
| Streak | white | colorless |
| Crystallography | orthorhombic, hexagonal | orthorhombic |
| Refractive Index | 1.53, 1.685 | 1.614, 1.636 |
| Hydrous | No | Yes |
| Colors | common: green sometimes: red, blue less common: gray, pink, brown, white, orange, purple, yellow, lavender, colorless |
common: blue, brown, yellow sometimes: gray, pale, beige, white, colorless, green |
| Solubility | Soluble in acids | Soluble in common acids. |
| Category | carbonate | sorosilicate |
| Birefringence | δ = 0.156 | δ = 0.022 |
| Fracture | subconchoidal | subconchoidal, uneven |