Everything about Psilomelane totally explained
Psilomelane, also known as
black hematite, is a group name for hard black
manganese oxides such as hollandite and
romanechite. Psilomelane consists of hydrous
manganese oxide with variable amounts of
barium and
potassium.
Formula
Generalized formula may be represented as Ba(Mn
2+)(Mn
4+)
8O
16(OH)
4 or as (Ba,H
2O)
2Mn
5O
10. It is sometimes considered to be a hydrous manganese manganate, but of doubtful composition. The amount of manganese present corresponds to 70-80% of manganous oxide with 10-15% of available
oxygen.
Characteristics
Psilomelane is amorphous and occurs as botryoidal and stalactitic masses with a smooth shining surface and submetallic lustre. The
mineral is readily distinguished from other hydrous manganese oxides (manganite and wad) by its greater
hardness 5 to 6; the
specific gravity varies from 3.7 to 4.7. The streak is brownish black and the fracture smooth. Owing to its
amorphous nature, the mineral often contains admixed impurities, such as
iron hydroxides. It is soluble in
hydrochloric acid with evolution of
chlorine gas.
History and occurrence
The name has reference to this characteristic appearance, from the
Greek for (naked, smooth) and (black); a
Latinized form is calvonigrite, and a
German name with the same meaning is
Schwarzer Glaskopf.
It is a common and important
ore of manganese, occurring under the same conditions and having the same commercial applications as
pyrolusite. It is found at many localities; amongst those which have yielded typical botryoidal specimens may be mentioned the Restormel iron mine at
Lostwithiel in
Cornwall,
Brendon Hills in
Somerset,
Hoy in
Orkney, Sayn near
Coblenz, and Crimora in Augusta county, Virginia. With pyrolusite it's extensively mined in
Vermont,
Virginia,
Arkansas, and
Nova Scotia.
Psilomelane is also cut, shaped, and polished for a variety of jewelry applications.
Further Information
Get more info on 'Psilomelane'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://psilomelane.totallyexplained.com">Psilomelane Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |
