What does Black Tourmaline look like?
Black tourmaline is quite a popular mineral. Many will often find black rocks out in nature and wonder if they have stumbled onto black tourmaline. This mineral has some very distinct features that will let one know if they are holding black tourmaline or not.
Black tourmaline looks like black rock that has lines going in one direction on the minerals surface. Often black tourmaline will look like a rod where these lines will follow the length of the rod. Sometimes black tourmaline will look like smaller shiny crystals or can be somewhat dull in appearance.
These lines are really the defining visual feature that will let you know if you are holding black tourmaline. A lot of black tourmaline in general will be elongated parallel lined crystals that often will have a vitreous luster.
Black Tourmaline
Black tourmaline is a silicate mineral unique by its presence of sodium iron. Also called Schorl, black tourmaline is by far the most abundant variety of tourmaline available on our earth. Its visible outer lines flowing in the direction of the mineral are a notable visible feature of the mineral.
Black tourmaline is formed through what’s known as the hydrothermal process. This is where vapor from heated water finds its way into cracks and pockets of air in host rock. Crystals form in these open spaces.
Tourmaline in general has a very complicated chemical formula. (Ca,K,Na, [Vacancy])(Al,Fe,Li,Mg,Mn)3(Al,Cr,Fe,V)6
(BO3)3(Si,Al,B)6O18(OH,F)4
If you note, we have what is called a “vacancy” in the formula. This vacancy is a defect in the chemical structure. The defect is from a missing atom from one of the crystal lattice sites.
As an educated guess, so don’t quote me on this, as I tried to research this a little and found no solid answer… It could very well be that this vacancy, or crystalline defect, might be what causes the visible lines in black tourmaline. As the crystal forms in an elongated fashion, it continues to defect on that lattice site causing those visible lines. Again, just an educated guess.
Larger specimens of black tourmaline that are broken can show the visible lines within the specimen. This makes the appearance of multiple small crystal rods that make up the entire larger specimen.
Can I do Anything with Black Tourmaline?
Black tourmaline is often used as a display specimen or in jewelry. Since it is such a unique mineral, often black tourmaline will simply be displayed around the home. Black tourmaline as jewelry is used in rings, necklaces, pendants, earrings, and other jewelry.
The only problem with using black tourmaline in jewelry is you will lose that unique lined look. This of course will be the fact that it has to be cut, smoothed, and polished to be faceted.
Black tourmaline can go in water. This means you can also wash and clean your black tourmaline if needed. You will want to be cautious as you do so as many specimens of tourmaline can flake or loose pieces from those lines running down your specimen.
Those lines running down the outside of your specimen are generally not as stable as you would think. Black tourmaline is considered to be a brittle mineral, many specimens can chip or flake if you are too rough while cleaning it.
Many black tourmaline specimens can break and chip if you drop it. Being a very brittle mineral, if dropped it can even break into many pieces. If you have a very nice longer specimen and drop it, I can guarantee it will ruin your day.
For some of you rock tumblers out there, black tourmaline can be tumbled. I do not know why you would want to, but it can, as tourmaline has a Mohs scale hardens of 7 to 7.5. When black tourmaline is tumbled, all those lines that make it look like tourmaline will be gone.
Black Tourmaline Properties
 | |
| Bornite Scale Mohs Hardness: | 7 – 7.5 |
| Specific Gravity: | 3.06 – 5.1 |
| Bornite Streak: | White |
| Fracture: | Uneven, Conchoidal, Brittle |
| Bornite Luster: | Vitreous, Resinous |
| Crystal System: | Trigonal |
| Bornite Chemical Formula: | (Ca,K,Na, [Vacancy])(Al,Fe,Li,Mg,Mn)3(Al,Cr,Fe,V)6 (BO3)3(Si,Al,B)6O18(OH,F)4 |
| Other Tourmaline Properites. | From Mindat.org |
Colors of Tourmaline
Tourmaline does come in many different colors such as black, clear, red, brown, orange, yellow, blue, green, purple, and pink. These colors can often range in hue, but what makes tourmaline unique is that one single crystal can have two to even three different colors.
Since roughly 95% of tourmaline found is black, you can bet that the other colors of tourmaline are well sought after by collectors. Those crystals that form two to three different colors on one crystal are quite a sight. Many like to pick up specimens and even jewelry created from this duel or three different color mineral.
Black tourmaline will not fade in sunlight. However, if other colors of tourmaline have prolonged exposure to sunlight, they can fade. Minimize exposure to sunlight for all your tourmaline jewelry.
Black Tourmaline Confusion
Very often people will confuse obsidian and black tourmaline. Obsidian is a rock that can be quite common in some areas and it will often be confused with tourmaline.
The easiest way to determine if you have obsidian or tourmaline will be by its appearance. Obsidian is smooth and can look like glass and does not take a crystal form like black tourmaline. Obsidian will also break into glass looking shards that can be very sharp.
For more information on obsidian, I have written an article. “All About Obsidian”. This can help you go into a little more understanding about the rock.
Black tourmaline is not coal, and really nothing like coal. Some have made this assumption due to the visual uniqueness of this mineral. Coal is much softer, not in crystal form, and will not have those unique lines you will see with black tourmaline.
Price of Black Tourmaline
Black Tourmaline is fairly cheap and not too expensive. Other tourmaline specimens that contain different colors and even express dual or three colors on a crystal can get pricy. Expect to pay anywhere from $10 a carat to even $350+ per carat when cut and put into jewelry.
How they price tourmaline crystals and jewelry is beyond me. I have seen a nice pink example, around 2 carats, go for $30 to $40. While other pink examples run up to several hundred dollars. I have seen one fairly hefty gold ring with a multi-color orange, green, and yellow tourmaline gem at an ask price of almost $18,000.
It is my guess that some colors of tourmaline, size, clarity, and other factors will come into play on price. There is also the thought of some of the cheaper ones being a fake or maybe even manufactured.
