xUmp.com Logo

TODAY'S COUPON: SAVE ADDITIONAL 10% OFF with coupon code: BACK2SCHOOL2019 [Expires tonight at 11:59PM. Online orders only.]
Black Tourmaline - Large Chunk (2-3 inch) - Image One
Share this product:

Black Tourmaline - Large Chunk (2-3 inch)

by xUmp.com   Item#: 15748  
List Price:$15.99
Sale Price: $10.99 /each
You Save: $5.00 (31%)
SOLD OUT Check back in 5 to 10 days to order this item.

This large chunk of Black Tourmaline, 2-3 inches in diameter, is great for any mineral collection.

In its natural state, all Tourmalines are characterized by parallel ridges (striations) which run the length of the crystal. Tourmaline forms in igneous and metamorphic rocks and veins, and have a different shaped top than the bottom of the crystal. Another interesting characteristic is that this stone is a pyroelectric which means that when heated, a positive charge develops at one end and a negative charge at the other.

FOUND IN: TANZANIA, MADAGASCAR, BRAZIL, AUSTRALIA, SRI LANKA, RUSSIA & USA

Tourmaline’s name comes from the Sinhalese word “turmali,” which means “mixed.” Tourmaline, occurring in more colors and combinations of colors than any other gemstone variety, lives up to its name. Known for centuries, tourmaline first gained popularity when the Dutch began to import it in the early 17th century from Sri Lanka . Tourmaline is actually the name of a group of related mineral species. In gemological practice, individual species names are not used. Instead, all are simply termed tourmaline.

Color is the major characteristic for tourmaline. This stone is found in more hues, shades and nuances than any other gem.

Black Tourmaline Specifications:

  • Moh’s hardness: 7 – 7½
  • Specific gravity: 3.02 – 3.24
  • Cleavage: None
  • Fracture: Uneven, Small Conchoidal, Brittle
  • Crystal system: Hexagonal (Trigonal)
  • Chemical composition: SiO2 silicon dioxide (NaLica) (Fe11 Mg MN Al) Al ((OH) (BO) Si6 O18)
  • Refractive index: 1.554 – 1.553
  • Double refraction: -0.014 to -0.044
  • Dispersion: 0.017


Age:
14 +
Box Size:
3.00 x 3.00 x 3.00 inches
7.62cm x 7.62cm x 7.62cm
Weight:
0 lb 10 oz
0.28 kg

Customer Reviews


There are no customer reviews for this product. Be the first one to write one!

FEATURED PRODUCTS

Super Science Magnet Kit.

$19

Super Science Magnet Kit

Exciting magnet exploration for ages 8 and up!

Y-Ball Magnetic Puzzle.

$29.99

Y-Ball Magnetic Puzzle

The Y-Ball Magnetic Puzzle is the perfect creativity tool for innovators, artists, engineers, writers, students, and you!

The Original Hoberman Sphere.

$37.99

The Original Hoberman Sphere

The Hoberman Sphere expands and contracts with a magical motion so fluid and simple that kids can't help but play with it for hours.

Meccano Super Construction Set - 638 Pieces.

$99.99

Meccano Super Construction Set - 638 Pieces

This SUPER Erector Construction set is one of the best you'll find anywhere!

Tripod Periodic Table Lamp.

$29

Tripod Periodic Table Lamp

Illuminate both your room and your mind with this ingenious Periodic Table Lamp.

Space Wonder Gyroscope.

$9.99

Space Wonder Gyroscope

This high precision gyroscope will amaze you with rotational speed and ease of precision.

xUmp.com Logo


Join our tribe:

SIGN-UP & SAVE

Sign-up for our weekly discounts and promotions email newsletter.



xUmp.com Catalog

CATALOG

View xUmp science supplies catalog

At xUmp.com, we are passionate about science. We believe in hands-on learning and making science fun. - Anton Skorucak, Physicist and Founder

At xUmp.com you will find a large selection of scientific products carefully curated by real scientists and educators. We sell everything from educational toys, teacher supplies for science classroom, lab equipment, science toys, science fair supplies, classroom equipment, chemistry glassware, chemistry lab equipment, physics demos, electronics supplies, robots, science kits to geeky science gifts.