Minerals
TopGeneral Information
Tourmaline is a silicate mineral that originates from Sri Lanka and was shipped to Europe by the V.O.C. for collections and jewellery. 95% of the natural tourmaline consists of schorl, a distinct type of tourmaline. There are also dravite and elbaite as important types.[1]
TopChemical & Physical Information
| Trivial Name | Tourmaline |
| Chemical Name | Silicate |
| Chemical Formula | (Ca,K,Na,-)(Al,Fe,Li,Mg,Mn)3(Al,Cr, Fe,-)6(BO3)3(Si,Al,B)6O18(OH,F)4 |
| Density | 2,82-3,32 g·cm-3 |
| Molar mass | - |
| Hardness | 7-7,5 |
| Crytal system | Trigonal |
| Unit cell | ? |
| Crystal habit | Parallel and elongated, needle-shaped prisms. |
| Fracture | Uneven, conchoidal and brittle. |
| Cleavage | Unclear |
| Colour | Black, green, purple, pink and brown. |
| Luster | Glass |
| Streak | White |
| Opacity | Subtransparent to translucent. |
| Safety | Safe |
| Extra | Semi-precious. |
Photos
(1 cm)
(4 cm)
Sources
[1] Wikipedia
[2] Specimen from my personal collection, photo taken by me.
