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Native Silver (tarnished yellow) overgrown by Nickeline (pink) and Rammelsbergite (whitish grey rim on Nickeline) and Gersdorffite (light grey, euhedral crystals) and partially replaced by intergrown Acanthite (dull, scratched grey) and Stephanite (slightly lighter, "cleaner" grey)

Locality: Easter-Duffy Deposit, Greater Slave Lake, Northwest Territories, Canada

Plane Polarized Reflected Light, 50X Magnification

Acanthite

Ag2S

Locality:

Mascot Mine (Gorham Lead mine; Galena King mine), Gorham, Coos Co., New Hampshire, USA

Largest crystal 0.5 mm

Tom Mortimer's Photo

Acanthite is a form of silver sulfide a common silver mineral in moderately low-temperature hydrothermal veins and in zones of supergene enrichment. Typically found as pseudo-cubic and pseudo-octahedral crystals, paramorphic after argentite.

#Acanthite #USA #New Hampshire #silver #earth #art #science #love #geology #rock #minerals #crystals

Acanthite Imiter Mine, Ouarzazate Province, Souss-Massa-Draa Region, Morocco, Africa

#Acanthite #minerals #crystals #geology

Ohh boy...

Well guys, I’m currently standing at some 66k followers. I don’t think anything on here is flagged, but I don’t know how to tell (I have tagged rocks as “sexy” and “this looks like a penis” after all). I imagine after purge night many of you could disappear. For the bots, meh, but for all you real people I’m so sorry tumblr has not acted maturely and hired mods like basically every other website and is now resorting to killing their business model.

Anyway, here’s a neat looking rock.

Acanthite, Pearceite Uchucchacua Mine, Oyon Province, Lima, Peru

#Acanthite #Pearceite #Lima #Peru #bad tumblr

Native Silver Wire with Acanthite

Locality: Kongsberg, Buskerud, Norway

Size: 3.5 × 2.0 × 1.7 cm

#Native Silver #Acanthite #Silver #Kongsberg #Norway #Metallic #Minerals #Crystals #Gems #Gemstones #Science #Nature #Matrix #Geology #Natural beauty #hematitehearts #Mineralogy #Rockhound

Acanthite

While it may surprise you to know that the main ore of silver is the lead sulphide Galena (https://bit.ly/2HM9r1D), the silver sulphide in these pictures is the second most common. Even then much of the silver that comes as a by product from processing lead sulphide exists as minute inclusions of Acanthite diffused in the crystals This composition has 2 forms, depending on the temperature of crystallisation of the hydrothermal vein in which it forms.

Below 173 degrees it forms as Acanthite, above it as Argentite, which then cools to the only stable form at room temperature and changes crystal structure and identity as it does so. It was first described in 1855 from a type locality in Bohemia (now in the Czech Republic, then the Hapsburg Empire).

The name comes from the Greek for thorn, since the crystals are often that shape, though dendritic or arborescent tree shapes oftwen formed of distorted octahedra (a remnant of the Argentite crystal shape) and thin skeletal crystals are also known. Colour is lead grey to black, and the mineral is very soft (2.5 on Mohs scale, and sectile, it can be easily cut with a knife) while also feeling very dense in the hand. You have of course all seen it, as part of the dark tarnish that develops on silver items or jewellery.

Other notable localities include Germany, Mexico, the United States, Canada, Cornwall, Kongsberg in Norway and Chile. Good crystals are rare, most material being massive vein filling. The 4.5 x 3.5 x 2.0 cm sample that somewhat resembles a vulture's head in the photos was mined in Mexico. The shape comes from natural etching, and the Acanthite sits on a pretty gangue of bright white quartz.

Loz

Image credit: Spirifer Minerals

https://www.mindat.org/min-10.html http://www.minerals.net/mineral/acanthite.aspx http://www.galleries.com/Acanthite https://bit.ly/2vsaUHZ