Riebeckite
Riebeckite is a sodium-rich member of the amphibole group of silicate minerals, chemical formula Na2(Fe2+3Fe3+2)Si8O22(OH)2. It forms a series with magnesioriebeckite. It crystallizes in the monoclinic system, usually as long prismatic crystals showing a diamond-shaped cross section, but also in fibrous, bladed, acicular, columnar, and radiating forms. Its Mohs hardness is 5.0–6.0, and its specific gravity is 3.0–3.4. Cleavage is perfect, two directions in the shape of a diamond; fracture is uneven, splintery. It is often translucent to nearly opaque.
Name and discovery
It was first described in 1888 for an occurrence on Socotra Island, Aden Governorate, Yemen and named for German explorer Emil Riebeck (1853–1885).
Occurrence
It typically forms dark-blue elongated to fibrous crystals in highly alkali granites, syenites, rarely in felsic volcanics, granite pegmatites and schist. It occurs in banded iron formations as the asbestiform variety crocidolite (blue asbestos). It occurs in association with aegirine, nepheline, albite, arfvedsonite in igneous rocks; with tremolite, ferro-actinolite in metamorphic rocks; and with grunerite, magnetite, hematite, stilpnomelane, ankerite, siderite, calcite, chalcedonic quartz in iron formations.
Podcasts:
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by A Home. A Heart. Whatever.
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by Enforcer
Crystaleyed
by: A Home. A Heart. Whatever.What once felt near in a former sentimental year
Slowly disappeared, but the more we try the more it's getting real
Words once felt near, by the way, I won't get hurt in here
My truth concealed but the more I try the more it's getting real
Somewhere there by your side
Somewhere there crystaleyed
We're somewhere there the way we were
Somehow, sometimes
We're somewhere there the way we were
Somehow, sometimes
A hundred heights from here I am still in love with you my dear
All you need is, all we need is, all I need is
Everything's revealed
Somewhere there by your side
Somewhere there crystaleyed
Somewhere there by your side
Leave me here paralyzed
This time is the first time to feel best, mine
Just the way it's got to be
It's for the first time I can rest, fine
Just the way it's got to be
Don't mind about those rhymes such hard to find
Just the way it's got to be
Always on my mind and for all time
That's the way it's got to be