Taos Rockers
229 A Camino de la Placita, Taos, NM, 87571
20180806_144448.jpg

Tos Rockers' Mineral of the Month Blog

Typically each month, a mineral is showcased in our storefront as our Mineral of the Month. Come in to check out our display of the wide variety of differences found in the mineral due to localities in which it is found, as well as the different habits that the mineral takes on. Here, on our blog we present you with a write-up of information along with pictures showcasing each mineral chosen. We encourage and welcome your input! At the bottom of each page you will find a comments section. Happy sharing!

Click photos to view blog posts.

 

July ~ Beryl

MINERAL OF THE MONTH – BERYL

IMG_0114.JPG

Taos Rockers mineral of the month is Beryl.  The name "beryl" is derived from the Greek ήρυλλος beryllos which referred to a "precious blue-green color-of-sea-water stone" - that name was applied to a variety of blue-green stones in antiquity.  Later the term was exclusively adopted for the mineral Beryl.

·  Mineral: Beryl

·  Chemistry: Be3Al2(Si6O18)

·  Class: Cyclosilicate

·  Crystal system: Hexagonal

·  Color: Colorless, green, blue, yellow, white, pink, red

·  Refractive index:  1.577 to 1.583

·  Luster: Vitreous, Sub-vitreous, Waxy, Greasy

·  Specific gravity: 2.63-2.92

·  Mohs Hardness: 7.5 - 8

·  Cleavage: Imperfect

·  Fracture: Conchoidal

 

Beryl is a member of the hexagonal crystal system - typically forming hexagonal columns (but also occurring in massive habits).  The crystal structure consists of Si 6 O 18 {\displaystyle {\ce Si6O18 rings, which are linked to one another by beryllium and aluminum.  The Si 6 O 18 {\displaystyle {\ce Si6O18 silica tetrahedra are stacked on top of one another in perfect alignment along the c-axis, creating channels in the crystal structure that run parallel to the c-axis.  These channels permit a variety of ions, neutral atoms, and molecules (especially water and alkali cations such as sodium, potassium, cesium and rubidium) to be incorporated into the crystal thus disrupting the overall charge of the crystal permitting further substitutions in aluminum, silicon, and beryllium sites in the crystal structure.  Increasing alkali content within the silicate ring channels causes increases to the refractive indices and birefringence.

 

The major economic use of beryl is as a gemstone.  It is also a secondary source of beryllium - bertrandite being the primary source.  It is one of the most important gem minerals, and a variety of names, loosely based upon their color, has been incorporated into the industry and popular vernacular.

 

            VARIETY NAME      COLOR                                              CAUSE OF COLOR

            Emerald                     green                                                              Cr3+ or V3+

            Aquamarine              greenish blue to blue                                  Fe2+ 

            Morganite                  pink to orange                                              Mn2+

            Red Beryl                  red                                                                  Mn3+

            Heliodor                     yellow to greenish yellow                           Fe3+

            Goshenite                 colorless                                                        --

 

Emerald and Aquamarine are the most popular.  It appears that emeralds are second only to diamonds in terms of the dollar value imported into the United States.

Aquamarine

Aquamarine

Morganite, Emerald

Morganite, Emerald

Beryl on Muscovite

Beryl on Muscovite

Beryl can be difficult to identify and may be confused with apatite.  The physical properties of Beryl useful in identification of the mineral include  a prismatic crystal habit, with flat terminations and lack of striations, hexagonal form, high hardness and rrelatively low specific gravity.  The latter two properties can be helpful for identifying massive specimens.

The  presence of beryllium, the key element in the formation of Beryl, limits the geological occurrence of the mineral.  Most of the beryl varieties occur within granitic pegmatites.  Emeralds are formed where carbonaceous rocks (shales, limestone and marble) have been subjected to regional metamorphism. The carbonaceous material providing the chromium or vanadium needed to color the emerald.  Red Beryl occurs in topaz-bearing rhyolites.  Beryl is often associated with tin and tungsten ore bodies.  Most ore beryl occurs in massive pegmatite zones where crystals may reach considerable size. 

Locations for Beryl are numerous.  Some of the more important locations include Brazil and San Diego County, California, Canada,  Russia and the Ukraine, numerous localities in southern Africa as well as in Afghanistan, China and Pakistan.  Other localities in the US include Mt. Antero in Colorado, the Sawtooth Mountains in Idaho, the Harding mine in Taos County, New Mexico, and the New England pegmatites especially in Maine. New England's pegmatites have produced some of the largest beryls found, including one massive crystal from the Bumpus Quarry in Albany, Maine with dimensions 5.5 by 1.2 m (18.0 by 3.9 ft) with a mass of around 18 metric tons; it is New Hampshire's state mineral. As of 1999, the world's largest known naturally occurring crystal of any mineral is a crystal of beryl from Malakialina, Madagascar, 18 m (59 ft) long and 3.5 m (11 ft) in diameter, and weighing 380,000 kg (840,000 lb)

Some of the locales from which specimens of Beryl are available at Taos Rockers include:

Colorado

New Mexico

Brazil

Namibia

Pakistan                   

Afghanistan             

 

Aquamarine is a birthstone for the month of March and the gemstone of the 19th Anniversary.  Emerald is a birthstone for the month of May and the gemstone of the 35th Anniversary.

 

Melody, in her book Love Is In The Earth, says of the Beryls:  "Aquamarine is a 'stone of courage'...Emerald is a 'stone of successful love'...Red Beryl (Bixbite) is a 'stone of love for the new age'...Morganite is a 'stone to tell the stories' and Goshenite 'encourages truth in ones world'". 

 

 

 

 

 

References:  Beryl and its Color Varieties - Lapis International, LLC; mindat.org; wikipedia.org; Love is in the Earth - Melody; and geology.com