AllMineralsRock
Amethyst Vs. Tourmaline
Amethyst is a very popular gemstone composed of silicon dioxide.[1] Tourmaline is also a very popular gemstone and its chemical composition is boron silicate.[2]
Quick Facts on Differences of Amethyst and Tourmaline
For a quick recap of the differences amethyst and tourmaline:- While both amethyst and tourmaline can be translucent or transparent, tourmaline can be opaque.
- For chemical formulas, amethyst is SiO2 while tourmaline can be (Ca, Al, B)6O18(OH, Cr, F)4, Fe, Fe, K, Li, Mg, Mn)3(Al, Na)(Al or V)6(BO3)3(Si.
- Amethyst can be commonly purple while tourmaline can be commonly red.
- Amethyst's rarity is less rare than tourmaline.
- Amethyst's specific gravity is lower than tourmaline - amethyst is 2.651 and tourmaline ranges from 2.82 to 3.9.
Quick Facts on Similarities of Amethyst and Tourmaline
The similarities of amethyst and tourmaline include:- In terms of crystallography, amethyst and tourmaline both can be hexagonal or trigonal.
- In terms of luster, amethyst and tourmaline both are vitreous.
- Amethyst and tourmaline both streak white.
- Amethyst's hardness overlaps with tourmaline - amethyst is 7 and tourmaline ranges from 7 to 7.5 on the Moh's scale.
Summary of Amethyst
Amethyst is a mineral that belongs to the quartz family and is known for its purple color. The color of amethyst can range from pale lilac to deep purple, depending on the concentration of iron and other trace elements present in the crystal. It is a popular gemstone and is often used for jewelry, decorative purposes, and spiritual healing.Summary of Tourmaline
Tourmaline is a mineral that belongs to the silicate group and is known for its unique crystal structure and the wide range of colors it comes in. It is a complex mineral that contains boron, aluminum, and other elements. Tourmaline is found in many different parts of the world, including Brazil, Afghanistan, Pakistan, and the United States. The mineral can be identified by its prismatic crystal habit, which means that it has a long, column-like shape with flat faces on either end.Table Comparison of Amethyst vs Tourmaline
| Amethyst (src) | Tourmaline (src) | |
|---|---|---|
| Transparency | transparent, translucent | transparent, translucent, opaque |
| Chemical Formula | SiO2 | (Ca,K,Na)(Al,Fe,Li,Mg,Mn)3(Al,Cr,Fe,V)6(BO3)3(Si,Al,B)6O18(OH,F)4 |
| Chemical Composition | silicon dioxide | boron silicate |
| Specific Gravity | 2.651 | 2.82, 3.9 |
| Hardness | 7 | 7, 7.5 |
| Streak | white | white |
| Crystallography | hexagonal, trigonal | hexagonal, trigonal |
| Refractive Index | 1.544, 1.553 | 1.603, 1.82 |
| Hydrous | No | No |
| Colors | common: purple sometimes: lilac less common: pale, violet, red |
common: red sometimes: blue, black less common: gray, pink, brown, green, white, orange, purple, violet, yellow, colorless, multicolor |
| Category | silicate | cyclosilicate |
| Birefringence | δ = +0.009 (B-G interval) | δ = -0.018 to −0.040 |
| Fracture | conchoidal, uneven | conchoidal, uneven |