Skip to content

Sunday Daily Feed, October 15, 2017

October 15, 2017
The Rockhound Connection
 
and numerous quotes and images from my Facebook friends.
These are the images and quotes that appeal to my sensibilities or the lack thereof.
Thanks,

 

Enjoy!
 
Randy
 

Note:  When you cut and paste from various videos, you may get more than one image.

 
 
 
 

I like my agates to be colorful, polished, and well dressed. R
No automatic alt text available.

Image may contain: food
4 hrs ·Coyamito agate

Burmese Tourmaline Crystal (?)  Probably faceted.  R

Let the Buyer Beware!

No automatic alt text available.
 
 
 

“Beryl is a mineral composed of beryllium aluminium cyclosilicate with the chemical formula Be3Al2(SiO3)6. Morganite, also known as “pink beryl”, “rose beryl”, “pink emerald”, and “cesian (or caesian) beryl”, is a rare light pink to rose-colored gem-quality variety of beryl. The pink color of morganite is attributed to Mn2+ ions.” Wikipedia > R
Image may contain: flower

Morganite on albite with quartz and tourmaline, 11.4 cm, from Kunar Province, Afghanistan. Rudolf Watzl and Lisa Pammer collection, Anton Watzl Sr., photo.
 
 

 

Malachite is a copper carbonate hydroxide mineral, with the formula Cu2CO3(OH)2Chrysocolla is a hydrated copper phyllosilicate mineral with formula:  (Cu,Al)2H2Si2O5(OH)4·nH2O.”  Wikipedia > R
No automatic alt text available.

9 hrs ·
Malachite with Chrysocolla – partially polished Stalactite / Congo.
 
 

Yes! Yes! Yes! Green emerals from North Carolina! R
No automatic alt text available.

These three samples of emerald are from Hiddenite mine, Stony Point, North Carolina.
 

I just love fluorite, and garnets, and rocks, and minerals. Just one more please. R

Image may contain: food
2.73 KG Cave In Rock, Illinois – Raspberry Fluorite – Lets the Light Through – Phantoms – 9″Long x 5.25″ Wide x 3.75″ Tall – Comment or Dm for Inquiries.
 
 

https://www.facebook.com/natgeotravel/videos/10155273394273992/?hc_ref=ARRb-GTJed_gqyKliE3gxk5RErr4K8oGhIDbVbueD_-qwk5-XKBQEZRK01k7DkV9hiM&pnref=story


I wonder if it gets COLD in the winter time?  R



Exquisite Sky-Blue Aquamarine with Lustrous Tourmaline from the Recent Pocket found in Erongo, Namibia – $1900 delivered

 
 
 

https://www.facebook.com/YFMShareYourSound/videos/314427482359444/?hc_ref=ARShG3mJC1UVmiv4MeCJ-jh2NiQtrUyszXHA1hCnTHgusq4AD0oAnXsMJU_YQkdnjHo&pnref=story


And now from the Bluff Park Back Porch.  I better check my spoons?  Ha.  R
Antonio MiglioliOctober 13 at 1:33pm
e More
New interpretation of a sample I’ve already posted in the past. Miniatures, 37 mm long, showing two quarrels crystals of hematite on whose faces of pinacoide appear crystals in growth growth. A Classic of this fabulous location in Val Devero, which has provided new and very rare minerals (in particular arsenous and arseniti) unique in the world. The Ematiti of cervandone, although not presenting large crystals, are among the most beautiful in the world for paragenesis, sharpness, lucenteza and morphology. If anyone is interested, I remember the article recently appeared on pencil and related to the ematiti of the cervandone.
Leave a comment
from → Uncategorized

October 15, 2017 Weekly Geology Guest, Corundum

October 15, 2017
Greetings from the Bluff Park Back Porch, way up yonder on Shades Mountain (1,109′) in Alabama:
 
 
For the next several weeks we will delve into Industrial Minerals, While they are not glamorous, they are terribly important to our modern way of life. 
 
 


Typical examples of industrial rocks and minerals are limestone, clays, sand, gravel, diatomite, kaolin, bentonite, silica, barite, gypsum, and talc. Some examples of applications for industrial minerals are construction, ceramics, paints, electronics, filtration, plastics, glass, detergents and paper.

_____________________________________________________________

Corundum

Corundum is a crystalline form of aluminium oxide (Al
2
O

3) typically containing traces of iron, titanium, vanadium and chromium.[2][3] It is a rock-forming mineral. It is a naturally transparent material, but can have different colors when impurities are present. Transparent specimens are used as gems, called ruby if red and padparadscha if pink-orange. All other colors are called sapphire, e.g., green sapphire for a green specimen.”
“Because of corundum’s hardness (pure corundum is defined to have 9.0 on the Mohs scale), it can scratch almost every other mineral. It is commonly used as an abrasive on everything from sandpaper to large machines used in machining metals, plastics, and wood.”
“Corundum occurs as a mineral in mica schist, gneiss, and some marbles in metamorphic terranes

several corundum crystals

Several corundum crystals.jpg
2006 by Ra’ike

Red Corundum = Ruby

File:Corundum-180102.jpg
before 2010.  Rob Lavinsky, IRocks.

Red Corundum Crystal.

http://imgarcade.com/corundum-rock.html

Blue Corundum = Sapphire.

https://www.dakotamatrix.com/mineralpedia/5755/corundum

Blue Corundum Crystal.

Corundum Crystals.


Emery nail files: “Emery boards” are a manicure and nail-care product that is made by gluing abrasive papers to a thin piece of cardboard. They obtained their name in the 1800s when crushed emery was used as the abrasive. Today’s emery boards are not made with emery. Instead, many of them have a coarse side of synthetic corundum (aluminum oxide) and a fine side of garnet abrasive. Photo © iStockphoto / Acerebel.
emery boards
 
 

______________________________________________________________

List of Industrial Minerals
_________________________________________________________


Editors Note:  It is the intent of this site to keep this discussion as simple as possible, so as to educate the interested general public and not to discuss with the geology crowd the latest geologic theories and nuances.  Thanks, R
_______________________________________________________________
“No copyright infringement intended.
The rights belong to their respective owners”
 
Copyright Disclaimer: Under Section 107 of the Copyright Act 1976, allowance is made for “fair use” for purposes such as criticism, comment, news reporting, teaching, scholarship, and research. Fair use is a use permitted by copyright statute that might otherwise be infringing. Non-profit, educational or personal use tips the balance in favor of fair use.
_________________________________________________________________________
Author’s Request:  If you see any pictures that you know the source and photographer, let me know immediately.  Thanks!  R

Images have been searched by TinEye Reverse Image Search.  http://tineye.com/
_________________________________________________________________

 
We will now continue down the Industrial Mineral dusty trail and continue with Corundum.
 
 
 
Enjoy the adventure!
 
Thanks,
 

R

October 8, 2017 Weekly Geology Guest, Carbonatites

October 12, 2017
Greetings from the Bluff Park Back Porch, way up yonder on Shades Mountain (1,109′) in Alabama:
 
 
For the next several weeks we will delve into Industrial Minerals, While they are not glamorous, they are terribly important to our modern way of life. 
 
 


Typical examples of industrial rocks and minerals are limestone, clays, sand, gravel, diatomite, kaolin, bentonite, silica, barite, gypsum, and talc. Some examples of applications for industrial minerals are construction, ceramics, paints, electronics, filtration, plastics, glass, detergents and paper.

_____________________________________________________________

Carbonatite

This one is a new one to me.
Carbonatite ( /kɑːrˈbɒnətt/) is a type of intrusive or extrusive igneous rock defined by mineralogic composition consisting of greater than 50% carbonate minerals.
 
Economic Importance:   
Carbonatites may contain economic or anomalous concentrations of rare-earth elements, phosphorus, niobiumtantalum, uranium, thorium, copper, iron, titanium, vanadium, barium, fluorine, zirconium, and other rare or incompatible elements. Apatite, barite and vermiculite are among the industrially important minerals associated with some carbonatites.
 

Carbonatite from Jacupiranga Estado de São Paulo, Brazil. The specimen is 20 cm X 14 cm. Mineralogical composition: the black minerals are magnetite, the white are calcite and the green ones are olivine.
Carbonatite.jpg

2008. by Eurico Zimbres Zimbres
 
 

Carbonatite lava at Ol Doinyo Lengai volcano, Tanzania

2001.  by Thomas Kraft, Kufstein
 

The carbonatite complex of Sukulu, Uganda, as seen from Tororo Rock.
File:Sukulu1.jpg


Trivia:  Only one carbonatite volcano is known to have erupted in historical time, the active Ol Doinyo Lengai volcano in Tanzania. It erupts with the lowest-temperature lava in the world, at 500–600 °C.

______________________________________________________________

List of Industrial Minerals
_________________________________________________________


Editors Note:  It is the intent of this site to keep this discussion as simple as possible, so as to educate the interested general public and not to discuss with the geology crowd the latest geologic theories and nuances.  Thanks, R
_______________________________________________________________
“No copyright infringement intended.
The rights belong to their respective owners”
 
Copyright Disclaimer: Under Section 107 of the Copyright Act 1976, allowance is made for “fair use” for purposes such as criticism, comment, news reporting, teaching, scholarship, and research. Fair use is a use permitted by copyright statute that might otherwise be infringing. Non-profit, educational or personal use tips the balance in favor of fair use.
_________________________________________________________________________
Author’s Request:  If you see any pictures that you know the source and photographer, let me know immediately.  Thanks!  R

Images have been searched by TinEye Reverse Image Search.  http://tineye.com/
_________________________________________________________________

 
We will now continue down the Industrial Mineral dusty trail and continue with Corundum.
 
 
 
Enjoy the adventure!
 
Thanks,
 

R
from → Uncategorized

Wednesday Daily Feed, October 11, 2017

October 12, 2017
The Rockhound Connection
 
and numerous quotes and images from my Facebook friends.
These are the images and quotes that appeal to my sensibilities or the lack thereof.
Thanks,

 

Enjoy!
 
Randy
 

Admin:  Anyone who wants off or on this distribution list just let me know and either you will be removed or added.  R

Love those pyrite cubes.  R

Pyrite xx11- 23 mm, navajún, Spain

Cut Green Tourmaline = Nice.  R

No automatic alt text available.
Larry Woods is feeling happy with Aaron Sangenitto and Stacia Woods in Blanco, Texas.

11 hrs ·

This is one my favorite Tourmalines that I ever cut.. 49.73ct Brazilian Green Tourmaline.. 2006 AGTA Spectrum Awards.. abstract organic carving.. happy Tourmaline month!

Nice size trilobite. Wonder if it could/would nibble my toes? R

No automatic alt text available.
10 hrs ·

Nice Arctinurus from New York. Some restoration of tail, but this is a very large specimen.

Pick a color, any ol’ tanzanite color. R

No automatic alt text available.
18 hrs ·
Tanzanite From Merelani, Arusha, Tanzania.
Specimen its From diffrent angles show it color-changing properties Gorgeous!!
Photo: Watzl minerals

A real man cave.  R

Image may contain: 1 person, smiling, tree and outdoor
15 hrs ·
The Enchanted Cave (The world’s largest amethyst geode) and its owner Naren King.

A repeat of emerald and pyrite. Droll! R

No automatic alt text available.

Nice, but my mind has trouble believing that this is all natural?  R

Image may contain: flower
A bouquet of poker chip calcite and pyrite Natural and extremely rare from hubei provence China.
Credit: Jeff Wonders

Uluru Rock, Australia

No automatic alt text available.
Image may contain: outdoor and nature
Image may contain: sky, cloud, outdoor and nature
Image may contain: outdoor
Image may contain: mountain, sky, outdoor and nature
Image may contain: plant, sky, mountain, grass, tree, outdoor and nature
Image may contain: mountain, sky, nature and outdoor
Image may contain: sky, mountain, nature and outdoor
Uluru Rock, Australia | #Geology #Awesome #View
.
Uluru is predominantly composed of coarse-grained arkose (a type of sandstone with an abundance of feldspar) and some conglomerate. Iron-bearing minerals weathered by oxidation give the rock its red-brown rusty colour, though fresh rock surfaces are grey. It covers 3.3 square kilometres and is 9.4 kilometres around its base. It reaches 345 metres above the plains.
Over 600 million years ago large amounts of Central Australia were below sea level within the Amadeus Basin. Rivers brought large quantities of sedimentary material into the Amadeus Basin. 500 million years ago the Basin started to rise out of the sea, and the sediment from the rivers began to form alluvial fans. The sediment from which Uluru formed came from a section one of these alluvial fans. Over time the sea re-entered the Basin and more sedimentary material was deposited then lithified.
Between 300 and 400 million years ago there was a prolonged period of mountain building; the future Uluru was tilted at almost 90° to create the present vertical orientation of the strata.
There were millions more years of weathering but Uluru, Kata Tjuta (the Olgas, 35 km to the west) and Atila (Mount Connor, about 100km east of Uluru) were made of harder rock than that which surrounded them, so were less susceptible to erosion. The landscape was smoothed out by the wetter climate of 60-70 million years ago

Topaz Thursday, October 5, 2017

October 6, 2017
The Rockhound Connection
 
and numerous quotes and images from my Facebook friends.
These are the images and quotes that appeal to my sensibilities or the lack thereof.
Thanks,

 

Enjoy!
 
Randy
 
Topaz is a silicate mineral of aluminium and fluorine with the chemical formula Al2SiO4(F, OH)2.

No automatic alt text available.
Marc Allen Fleischer to The Rockhound Connection
PRECIOUS, PRECIOUS! Presented here are semi-gemmy, high-quality natural rough crystals of Imperial Topaz! Topaz commonly contains inclusions and gas bubbles – True Imperial Topaz is of medium reddish orange to orange-red color. All Topaz is Allochromatic and derives its color via trace elements (or defects) in its crystal structure rather than by elements found in its basic chemistry. Chromium causes pink – red – and violet to purple colors, and when both Chromium and color centers are present, then Topaz will be colored orange. As early as 1751 there were reports of “Brazilian Rubies” – which in actuality were richly hued orange to red Topaz crystals. Even to the present day, this sherry-colored varietal has only been found in deposits near the colonial city of Ouro Preto – the Ouro Preto area of Brazil is the world’s major commercial source of Imperial Topaz. Imperial Topaz, approximately 4.4 cm and 5.3 cm – Ouro Preto, Eastern Brazilian Pegmatite Province, Minas Gerais, Brazil courtesy of the Smithsonian National Museum of Natural History. Fleischer Museum Archive photo.

Topaz – Double Terminated, Etched Floater

No automatic alt text available.

Topaz – Double Terminated, Etched Floater
Agnus Dei Claim, El Paso Co., Colorado, USA
21.43 mm x13.54 mm x 10.03 mm
Collection of John L. Dolde

NFS — with Thomas Earl.

Large Cut Blue Topaz

Topaz – Double Terminated, Etched Floater has been unveiled 30 years after it was discovered
The stunning 9,381 carat stone will soon be on show in the National History Museum, so experts are unable to give an idea of its value because of insurance reasons.

Max Ostro discovered the flawless blue stone in its natural form deep in the Amazon rainforest in Brazil in the mid 1980s.

Hot Rocks.

No automatic alt text available.
Naturally occurring blue topaz is extremely rare and tends to be very pale yet blue topaz is one of the most popular and affordable colored gemstones used in jewelry today. The color of blue topaz is almost always the result of a process that involves the exposure of natural colorless topaz to one or a variety of radiations and a final heat treatment to burn off undesired brown and green overtones. The irradiation treatment produces a significant amount of radioactivity and depending on the origin of the original material, it may take several years of “cool off time” until the gems can be verified as safe and sold commercially. When it was the treatment first introduced, treated blue topaz sold for up to $50 per carat but oversupply led to a collapse in prices essentially making irradiated topaz a mass-market gemstone and one of world’s most popular gemstones.
View Blue Topaz inventory –> http://bit.ly/IJgaK7
Image may contain: plant and flower
This topaz from Brazil was found in the 1940’s, along with some of the giant topaz specimens seen in major museums. This one is about 33 cm tall and weighs about 10 kilos, as I recall. An Easter table in Maine, 1986.

No automatic alt text available.

#mineralmonday

Mineral: Topaz

Information: Topaz(orange mineral in picture) is a well-known mineral by collectors, and occurs in large and beautifully shaped colored crystals. Gem quality topaz most commonly occurs in nature as a colorless crystal. When cut as a gemstone these colorless specimens generally have the lowest value. A significant amount of natural topaz also occurs in a color range spanning from yellow to brown. Small amounts of natural blue and pink topaz are found but the abundance of natural stones in these colors is very low. Those colors are formed from lighter-colored stones that undergo irradiation and heat treatment. There are many stones on the market that are heat treated to get their color, so be careful and aware of this when buying. If you are wanting to collect natural stones, then be aware of the misleading information that surrounds some gems in the market! The color of some Topaz specimens fade upon prolonged exposure to light.

Topaz is a silicate mineral most often found in igneous rocks of felsic composition. Topaz crystallizes in the orthorhombic system, and its crystals are mostly prismatic terminated by pyramidal and other faces. It is also found in some hydrothermal veins and the hydrothermally altered rocks that surround them. It is a common mineral of pegmatites and also found in the cavities of rhyolite and granite. Topaz is not an abundant mineral, but occurs worldwide in the type of rocks that are listed above. Topaz crystals in a matrix are rare and very much desired, since the perfect basal cleavage of Topaz causes it to separate from its base and form loose crystals. As always, make sure that when collecting topaz (any crystals for that matter), you take the right precautions to protect the specimens upon removal. Getting out topaz in the matrix can make your pieces very valuable compared to single crystals. Precautions must also be taken not to damage specimens when faceting, for pressure or improper faceting can cause a crystal to cleave and become ruined. There has been many times when clear Topaz and clear Quartz have been confused for one another, so do a specific gravity test to eliminate one of the two options!

According to the Roman author Pliny, the word Topaz derives its name from the Island of Topazos in the Red Sea, where it was first found, and he says the word Topazein means “to seek after” the island being so often lost amidst fogs. Some pirates who were weather-bound on this island and hard-pressed by famine, in tearing up roots for food accidentally discovered a yellow stone (believed to now be chrysolite: yellowish olivine) that was called topaz. The gem was called by Pliny “The Stone of Strength,” and he describes as the most valuable, stones that have a predominating tint of orange in their coloring. Albertus Magnus recommends it as a cure for gout, and Camillus Leonardus as a charm against hemorrhoids; lunacy, and sudden death; also to bring riches to its wearers, and the favors of princes. Alternatively, the word topaz may be related to the Sanskrit word “tapas”, meaning “heat” or “fire”! In the Middle Ages, the name topaz was used to refer to any yellow gemstone, but in modern times it denotes only the mineral Topaz.

Mineral Data:
Chemical Formula: Al2SiO4(F,OH)2
Composition: Aluminum fluoro-hydroxyl-silicate
Color: Colorless, white, yellow, orange, brown, pink, light purple, gray, light blue, greenish blue, green. Occasionally multicolored.
Streak: Colorless
Hardness: 8
Crystal System: Orthorhombic
Specific Gravity: 3.4 – 3.6
Luster: Vitreous
Cleavage: 1,3 – basal
Fracture: Subconchoidal
In Group: Silicates; Nesosilicates
Important Features: Great hardness and perfect basal cleavage
Environment: In igneous environments in granite pegmatites and in rhyolite. Occasionally in sedimentary alluvial deposits due to weather resistance
Rock Type: Igneous

PHOTO CREDIT: FMI/James Elliott MIM Museum

-Follow us for more educational posts at: https://www.facebook.com/ATRelicHunters

*Be sure to follow us on our other pages @
-Twitter: https://twitter.com/ATRelicHunting
-Instagram: https://instagram.com/at_relichunting/
-Youtube: https://www.youtube.com/channel/UCAzF3fEIUxL42xTOmStNJ9g

Imperial Topaz – Ouro Preto Brazil – 2.5 x .7 x .4 cm – very clean, great color, great termination – intense color down the c-axis – $135 + shipping

No automatic alt text available.

8.02ct Very Fine “Ouro Preto” Imperial Topaz

No automatic alt text available.

Peach Topaz

99.76ct Apricot Peach Topaz from the Tribute Pocket, Pikes Peak CO.  Photo by – Tino Hammid

Golden Topaz from Juab County, Utah

Image may contain: night
Golden Topaz from Juab County, Utah

https://upload.wikimedia.org/wikipedia/commons/b/bd/Americantopaz.jpg
The American Golden Topaz, a 172-faceted topaz weighing 22,892.5 carats (4.57850 kg), is the largest cut yellow topaz in the world, and one of the largest faceted gems of any type in the world. Originating from Minas Gerais, Brazil, it was cut by Leon Agee over a period of two years from an 11.8 kg (26 lb avdp) stream-rounded cobble owned by Drs. Marie L. and Edgar F. Borgatta. I

Red topaz from Tepetate, Municipio de Villa de Arriaga, San Luis Potosí, Mexico

2010.  Rob Lavinsky @ IRocks.com

Blue Topaz from Erongo Mountain, Usakos and Omaruru Districts, Erongo Region, Namibia

2010.  Rob Lavinsky @ IRocks.com

Sherry-colored topaz from Maynard’s Claim (Pismire Knolls), Thomas Range, Juab County, Utah, USA

2010.  Rob Lavinsky @ IRocks.com

W is for Wednesday, October 4, 2017

October 5, 2017
The Rockhound Connection
 
and numerous quotes and images from my Facebook friends.
These are the images and quotes that appeal to my sensibilities or the lack thereof.
Thanks,

 

Enjoy!
 
Randy
 

Admin:  Anyone who wants off or on this distribution list just let me know and either you will be removed or added.  R

W

Wavellite is a phosphatemineral with formula Al3(PO4)2(OH, F)3·5H2O. It normally occurs as translucent green radial or spherical clusters.

Wavellite from the Avant Mine, Garland County, Arkansas, showing spherical structure (size: 3.4 x 2.0 x 1.1 cm)
Rob Lavinsky, iRocks.com – CC-BY-SA-3.0
Wavellite Locality: Avant Mine, Avant, Garland County, Arkansas, USA (Locality at mindat.org) Size: 3.4 x 2.0 x 1.1 cm. This superb toenail specimen of wavellite from the premier finds in Arkansas shows very plainly the internal structure of massed acicular crystals that grow radially out from the center. This is actually a “ball inside a ball” – you can see the thin “shell” of the original ball that was later enclosed. This split ball sits up perfectly on a natural base of matrix with a layer of wavellite on it. Ex. Feist Collection.
Rob Lavinsky at IRocks.

Wakabayashilite is a rare arsenic, antimonysulfide mineral with formula [(As,Sb)6S9][As4S5].

Wakabayashilite-Calcite-176729.jpg
Wakabayashilite, Calcite Locality: White Caps Mine, Manhattan, Manhattan District, Nye County, Nevada, USA (Locality at mindat.org) Size: 10.0 x 7.9 x 7.8 cm. A very rare cluster of bright orange Wakabayashilite on a cabinet specimen of contrasting massive calcite. Ex. Andrew Carnegie Collection.
Rob Lavinsky @ IRocks.com
 
 
 

Weddellite (calcium oxalate dihydrate)aka “Kidney Stone”.

I wonder why they hurt so much?
Surface of a kidney stone.jpg
2012.  by  Kempf EK
 
 
 

Wiluite is a dark green, brownish, or black blocky silicate mineral with formula: Ca19(Al,Mg,Fe,Ti)13(B,Al,[ ])5Si18O68(O,OH)10.
Wiluite-rh3-48b.jpg

Locality: Wilui River, Yakutxk, Siberia, Russia
2010.  Rob Lavinsky @ IRocks.com
 
 
 
 

Witherite is a barium carbonate mineral, BaCO3, in the aragonite group.
Witherite-65711.jpg

Witherite Locality: Mahoning No. 1 Mine (Minerva No. 1 Mine), Ozark-Mahoning Group, Cave-in-Rock Sub-District, Illinois – Kentucky Fluorspar District, Hardin County, Illinois, USA
2010.  Rob Lavinsky @ IRocks.com

Wolframite, (Fe,Mn)WO4, is an ironmanganesetungstatemineral

Wolframiteportugal3.jpg

Wulfenite is a lead molybdate mineral with the formula PbMoO4.

Wulfenite-tcw02a.jpg
Wulfenite Locality: near Urumqi, Kuruktag Mountains, Xinjiang Uygur Region, Northern China.
2010.  Rob Lavinsky @ IRocks.com
Not a very showy bunch, mostly rare, in Black and White.

Tourmaline Tuesday, October 3, 2017

October 4, 2017
The Rockhound Connection
 
and numerous quotes and images from my Facebook friends.
These are the images and quotes that appeal to my sensibilities or the lack thereof.
Thanks,

 

Enjoy!
 
Randy
 

Admin:  Anyone who wants off or on this distribution list just let me know and either you will be removed or added.  R

tour·ma·line, /ˈto͝ormələn/

noun

  • 1. a typically black or blackish mineral that occurs as prismatic crystals in granitic and other rocks. It consists of a boron aluminosilicate and has pyroelectric and piezoelectric properties.

Tourmaline Locality: Ambositra District, Amoron’i Mania Region, Fianarantsoa Province, Madagascar (Locality at mindat.org) Size: 5.7 x 4.7 x 0.3 cm. A spectacular slice from a large tourmaline with a cranberry red rind, bright pink just inside it, and yellowish-green center. It has been polished on both sides to a glassy luster.
260px
2010, Rob Lavinsky, IRocks.com

Elbaite with quartz and lepidolite on cleavelandite
2010.  Rob Lavinsky at IRocks.com

Tri-color elbaite crystals on quartz, Himalaya Mine, San Diego Co., California, US

Tourmaline gemstones – Mozambique

Two dark green rectangular tourmaline stones and one oval tourmaline stone.

Bi-Colored Tourmaline.
https://i1.wp.com/www.hotel-r.net/im/hotel/gb/tourmaline-6.jpg

Tourmaline Ring (?)
https://i0.wp.com/www.hotel-r.net/im/hotel/gb/tourmaline-16.png

Watermelon Tourmaline (Green on the inside and red on the inside).

Red Tourmaline Crystals

Elbaite, Blue Tourmaline, 1.54 carats.
https://upload.wikimedia.org/wikipedia/commons/f/f2/Elbaite-cktsr-11b.jpg
Locality: Neuschwaben (Neu Schwaben), Karibib District, Erongo Region, Namibia.  2010.  Rob Lavinsky at IRocks.com

For Sister Schorl, Black Tourmaline.