Charoite, Aegirine and Fedorite

ID	594
Mineral	Charoite Aegirine Fedorite
Location	Ural Mountains - Russia
Fluorescence	LW-UV: close SW-UV: close
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Mindat data

ID	972
Long ID	1:1:972:4
Formula	`(K,Sr,Ba,Mn)_15-16(Ca,Na)₃₂[Si₇₀(O,OH)₁₈₀](OH,F)₄ · nH₂O`
IMA Status	0
Occurrence	K-feldspar metasomatites at the contact of nepheline- and aegirine-syenites with limestones.
Other Occurrences	Potassic feldspar metasomatites
Industrial	Jewelry
Discovery Year	1978
Diapheny	Translucent
Cleavage	Good in three directions.
Colour	Violet to deep lilac, whitish-grey to brown
Hardness (min)	5.0
Hardness (max)	6.0
About the name	For the type locality, near the Chara River, Russia.
Crystal System	Monoclinic
Cleavage Type	Distinct/Good
Morphology	Fibrous, massive.
Thermal Behaviour	About 2.4% H2O is lost up to 300° and l.3% more to 600°. Small endothermic effects are noted at 440°, 760°, and 970°.
shortcode_ima	Cha

ID	31
Long ID	1:1:31:0
Formula	`NaFe³⁺Si₂O₆`
IMA Status	0 1
Description	Pyroxene Group. Clinopyroxene Subgroup. Both acmite and aegirine have been used as designations of pyroxenes close to NaFe3+Si2O6 in composition. Acmite has also often been used to refer to the brown variety with pointed terminations (usually {221} an...
Other Occurrences	Common in alkalic igneous rocks, carbonatites, and pegmatites; from regionally metamorphosed schists, gneisses, and iron formations; in blueschist facies rocks, and from sodium metasomatism in granulites; authigenic in some shales and marls.
Discovery Year	1821
Diapheny	Transparent,Opaque
Cleavage	Good on {110}
Tenacity	brittle
Colour	Dark green to greenish black, reddish brown, black
Hardness (min)	6.0
Hardness (max)	6.0
Lustre	Vitreous, resious
About the name	First described as acmit by P. H. Ström (1821) from Rundemyr, Øvre Eiker, Buskerud, Norway for a mineral earlier mentioned shortly by Strøm (1784, as "crystalliseret hornsteen eller brun kantet og riflet Schoel i quarz" (crystallized hornstone or brownish angular and grooved schorl in quartz)). Ström (1821) recognized it as a new mineral and suggested the name wernerin, after the German geologist, Abraham Gottlob Werner. But Berzelius (1821), who analysed the mineral, named it achmit after the Greek αχμη, spear point, due to the habit of the crystals. Later, in 1834, the priest and mineralogist Hans Morten Thrane Esmark found a new mineral on Låven, Langesundsfjorden, Norway which was described and given the name aegirine, after Ægir (Aegir), the sea god in Norse mythology because the type location was along the sea shore (Berzelius 1835). Acmite and aegirine were first believed to be two separate species, one belonging to the amphiboles (acmite) and the other to the pyroxenes (aegirine). This was the case until 1871 when G. Tschermak put forward evidence that acmite and aegirine both belonged to the pyroxenes and are the same mineral. Acmite has been considered as a variety of aegirine (historically acmite had priority, so it should have been the other way around).
Streak	Pale yellowish grey
Crystal System	Monoclinic
Cleavage Type	Distinct/Good
Fracture type	Irregular/Uneven
Morphology	Prismatic crystals, showing 110, with blunt to steep terminations, to 35 cm, striated lengthwise, can be bent or twisted. In sprays of acicular crystals, fibrous, in radial concretions.
Twinning	Simple and lamellar on {100}
UV	Not fluorescent in UV
Comment Luster	Slightly resinous
Publication Year	1821
shortcode_ima	Aeg
Group	Clinopyroxene Subgroup

ID	1467
Long ID	1:1:1467:6
Formula	`(K,Na)_2.5(Ca,Na)₇Si₁₆O₃₈(OH,F)₂ · 3.5H₂O`
IMA Status	0
Description	A white micaceous mineral. Structurally related to Reyerite Group.
Occurrence	Fenitized sandstone
Discovery Year	1965
Diapheny	Transparent,Translucent
Cleavage	{001}
Tenacity	flexible
Colour	White, colorless, bright red, raspberry red
About the name	Named in 1968 by A. A. Kukharenko, M. P. Orlova, and A. G. Bulakh in honor of mathematician, crystallographer, and mineralogist Evgraf Stepanovich Fedorov [December 22, 1853 Orenberg, Russia - May 21, 1919 St. Petersburg, Russia]. Fedorov was very interested in group theory and proved important concepts involved in polytypism and wallpaper theory later used in solving crystal structures.
Streak	White
Crystal System	Triclinic
Cleavage Type	Perfect
Fracture type	Micaceous
Morphology	Platy micaceous aggregates
Publication Year	1965
shortcode_ima	Fdr
Group	Fedorite Group

Price: € 18

Dimensions: Not registered

Weight: Not registered

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Notes:

Symbol	Element
Ca	Calcium
F	Fluorine
Fe	Iron
H	Hydrogen
K	Potassium
Na	Sodium
O	Oxygen
Si	Silicium
Sr	Strontium

Charoite, Aegirine and Fedorite

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