gems-and-geology-of-the-globe

[gems-and-geology-of-the-globe]

Stewartie & Phosphosiderite - From Portugal

Uniquely vibrant - An especially deep purple/ cobalt Stewarite on a gemmy and resinous Phosphosiderite.

Photo by Yaiba Sakaguchi

[gems-and-geology-of-the-globe]

Radiant Rhodochrosite - Northern Cape Province, So. Africa

From: N`Chwaning Mines, Kuruman, Kalahari manganese field, Northern Cape Province, South Africa Watch this specimen sparkle on video here, it’s gorgeous!!

Extraordinary specimen from the famous N'Chwaning mine in South Africa. Presence of dozens of centimetric caliweedrons completely gems, intact, lustrous, of an intense blood red color that contrast with their bright black Manganite gangue. Rhodochrosite covers almost the entire room! This piece is exceptional by the number of crystals and especially by the quality of them! Video to see absolutely to realize the effect produced. This specimen is of course sold with its custom-made engraved base made by us for optimal enhancement.

[gems-and-geology-of-the-globe]

Annabergite - Attica, Greece

Annabergite has a wonderful, bright green color. This characteristic color is easily noticeable and was used to spot veins of nickel-bearing ore. Annabergite, or "Nickel Bloom" as it is called by miners, is a weathering product of nickel-containing minerals such as niccolite, NiAs.

[gems-and-geology-of-the-globe]

Rare Double Opal Pineapple - White Cliffs, NSW, Australia

Valued at Aud $340,000 | One of the rarest and most fascinating types of opal comes in the shape of a palm-sized cluster of radiating points that resembles a pineapple. These "Opal Pineapples" are found only in the Cretaceous sediments of the White Cliffs in Australia & had their beginnings in an ice age.

In Australia, precious opal is found in Cretaceous age sandstones & mudstones. These sedimentary rocks were deeply weathered & this weathering released silica into the groundwater. Small faults & joints in the rocks formed pathways for movement of the groundwater as it penetrated downwards.

Impermeable barriers between the sandstone & the underlying rocks trapped the silica-carrying groundwater where it slowly hardened into a gel forming opal in veins & lenses.

Spectacular mineral replacement with opal can also occur. The so called ‘opal pineapples’ found at White Cliffs, NSW are opal pseudomorphs of the mineral Glauberite are examples of this.

[gems-and-geology-of-the-globe]

Iridescent Goethite - Graves Mtn. in Georgia , U.S.A.

Goethite is an iron hydroxide mineral that is commonly formed by the weathering of other iron-bearing minerals. These particular samples of goethite have a botryoidal habit and display iridescence, an optical effect caused by the interference of light against the minerals structure. 

[gems-and-geology-of-the-globe]

Indonesian Jasper - A Landscape in a Stone

Maligano jasper is a specific type of jasper found in Indonesia and forms in ancient volcanic hot spring areas. It is named after a small village in Sulawesi, Indonesia, and was found less than 10 years ago. Maligano is known for its contrasting hues of blue, yellow, red, green, and grey with brecciated patterning plus its fun dendrite patterns, making the stone often show various landscape and water scenes.

[gems-and-geology-of-the-globe]

Plumbogummite on Pyromorphite Crystal Formation - Bolivia

Plumbogummite is an extremely rare lead phosphate mineral that forms in trigonal crystal structures. Its blue-green color is gained from inclusions of Aluminum. This mineral was first discovered in 1819 by François Pierre Nicolas Gillet de Laumont, & named after the Latin words "plumbum" meaning lead & "gummi" meaning gum. This peculiar naming is due to its similarity to a coating of sticky gum on top of a crystal.

Plumbogummite is a pseudomorph mineral, meaning that it grows & replaces the spot of another mineral. This crystal commonly grows alongside Pyromorphite but has also been found in association with Mimetite, Wulfenite, Cerussite, Angelesite, & Dufitite. It is found in a few localities throughout the world, most notably France, China, Australia, Germany, Austria, & the United Kingdom. Although this crystal is often found in a blue-green color, is has also appeared in a pale yellow color in Bolivia.

[gems-and-geology-of-the-globe]

Vlasovite, Eudyalite, Gittinsite, Agrellite - From Quebec, Canada

[gems-and-geology-of-the-globe]

Plumbogummite Pseudomorph after Pyromorphite - from Yangshuo Mine, China

[gems-and-geology-of-the-globe]

Quartz, Hematite, Papagoite/Shattuckite, Ajoite, & Kaolinite

Polished specimen of quartz included by red hematite, pale-blue ajoite, dark-blue shattuckite and white kaolinite. Acquired in 1988 from a miner in Musina, South Africa who did not rate the specimens at all because the crystals were ugly, heavily encrusted with secondary overgrowths of chlorite and hematite. Only by polishing, was the interior revealed.

For more, see -> Gems & Geology of the Globe

[gems-and-geology-of-the-globe]

Gems & Geology of the Globe

Banded Amber with Termite Inclusions

Size: 5.7 cm by 10.7 cm by 3.5 cm

Locality:  Boyacá Department, Colombia.

[gems-and-geology-of-the-globe]

Aesthetic specimen of pyromorphite crystals from Saint-Salvy Mine, Occitanie, France

credit: Spirifer Minerals

[gems-and-geology-of-the-globe]

Azurite & Malachite Carved Crystal Skull

Azurite is a popular mineral whose name comes from its striking blue color. It is a copper-based mineral that is formed from weathering copper deposits. Azurite is also known as Chessylite. Azurite was first used as a pigment in Fourth Dynasty Egypt. It was used to make a pigment called Egyptian Blue. It can turn into malachite under certain conditions. It usually occurs with green Malachite, which may form green stains or specks on Azurite crystals or aggregates. The two minerals sometimes occur admixed or banded together, forming what is called "Azure-malachite" in the gem and mineral trades. A rarer Azurite mixture, known as "Bluebird", is Azurite mixed with dark red Cuprite. Azurite, "Azure-malachite", and "Bluebird" all have gem uses.

For more, see -> Gems & Geology of the Globe

[gems-and-geology-of-the-globe]

Chrysoberyl

Properties of Photography Properties of chrysoberyl. Alexandrite is the most famous and valuable variety of natural chrysoberyl. Named after Tsar Alexander II of Russia

-> Gems & Geology of the Globe

[gems-and-geology-of-the-globe]

Titanite on Albite

Haramosh Mountains, Pakistan

[gems-and-geology-of-the-globe]

Yellow Fluorite with Pyrite from Morocco

For more, see -> Gems & Geology of the Globe on tumblr

[gems-and-geology-of-the-globe]

Anglesite from Touissit dist., Oujda-Angad prov., Oriental, Morocco

Gemmy amber colored wedge-shaped crystals to 1cm in a cluster of at least 10 crystals. Of course the Anglesite from this locality were found in much larger crystals in the early 1980's to 5cm. Some of the crystals were treated (accidentally or on purpose) to bring out the color. This specimen was NOT treated as can be seen in a small chip off the crystal at the bottom, which internally shows the same color.

The mines around Touissit are classified by geologists as Mississippi Valley Type. As in the mines of Illinois, Kentucky and Tennessee, the Touissit district contain large mineable lead-zinc replacement deposits hosted within dolomite beds. Concentrations of ore are located along structured and are also stratigraphically controlled. In contrast to the US midwest MVT deposits, the Touissit deposits are fluorine deficient.

For more, see -> Gems & Geology of the Globe blog on tumblr