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|System:||Monoclinic||Colour:||Dark reddish brown to ...|
|Name:||Named in 1987 by Pete J. Dunn, Donald R. Peacor, Robert A. Ramik, Shu-Chun Su, and Roland C. Rouse for an old name of the town, "Franklin Furnace". The town became "Franklin [borough]" on April 23, 1913.|
Intergrown clusters or rosettes of dark red brown plates implanted on hodgkinsonite crystals in open cavities. A second much more uncommon find occurred as nearly black filamentous crystals associated with nelenite in open cavities. Franklinfurnaceite has the chlorite group structure, but has unusual chemical composition. It represents the very rare case of a zincosilicate, in which zinc atoms replace Si atoms in (SiO4) tetrahedra (Gaines et al., 1997).
Classification of Franklinfurnaceite
|Strunz 8th edition ID:||8/H.23-110|
|Nickel-Strunz 10th (pending) edition ID:||9.EC.55|
9 : SILICATES (Germanates)
E : Phyllosilicates
C : Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets
|Dana 8th edition ID:||22.214.171.124|
71 : PHYLLOSILICATES Sheets of Six-Membered Rings
4 : Sheets of 6-membered rings interlayered 1:1, 2:1, and octahedra
|Hey's CIM Ref.:||14.7.23|
14 : Silicates not Containing Aluminum
7 : Silicates of Ba, Sr and Zn
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Type Occurrence of Franklinfurnaceite
|Type Locality:||Franklin Mine, Franklin, Franklin Mining District, Sussex Co., New Jersey, USA|
|Year of Discovery:||1987|
|Associated Minerals at type locality:|
Physical Properties of Franklinfurnaceite
|Lustre:||Sub-Vitreous, Resinous, Waxy|
|Comment:||Luster is not vitreous|
|Colour:||Dark reddish brown to brownish black|
|Density (measured):||3.66 g/cm3|
|Density (calculated):||3.74 g/cm3|
Crystallography of Franklinfurnaceite
|Class (H-M):||2 - Sphenoidal|
|Cell Parameters:||a = 5.48Å, b = 9.39Å, c = 14.51Å|
β = 97.05°
|Ratio:||a:b:c = 0.584 : 1 : 1.545|
|Unit Cell Volume:||V 741.00 Å³ (Calculated from Unit Cell)|
|Morphology:||Platy pseudohexagonal crystals, also plumose to filamentous.|
|X-Ray Powder Diffraction:|
Optical Data of Franklinfurnaceite
|RI values:||nα = 1.792 nβ = 1.798 nγ = 1.802|
|2V:||Measured: 79° , Calculated: 78°|
|Maximum Birefringence:||δ = 0.010|
Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
|Surface Relief:||Very High|
|Dispersion:||r > v perceptible|
|Optical Extinction:||Z=b, Y = 29 degrees from c|
|Comments:||X very dark brown, Z deep brown, Y brown|
Chemical Properties of Franklinfurnaceite
|Simplified for copy/paste:||Ca2Fe3+Mn2+3Mn3+(Zn2Si2O10)(OH)8|
|Essential elements:||Ca, Fe, H, Mn, O, Si, Zn|
|All elements listed in formula:||Ca, Fe, H, Mn, O, Si, Zn|
Relationship of Franklinfurnaceite to other Species
|Member of:||Chlorite Group|
|Other Members of Group:|
|Related Minerals - Nickel-Strunz Grouping):|
|Related Minerals - Hey's Index Grouping:|
Other Names for Franklinfurnaceite
|Fluorescence in UV light:||Not fluorescent.|
|Health Warning:||No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.|
References for Franklinfurnaceite
American Mineralogist: 72: 812-815.
American Mineralogist: 73: 876-887.
Internet Links for Franklinfurnaceite
Localities for Franklinfurnaceite
The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
(TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.