Tunellite (original) (raw)
A valid IMA mineral species
About TunelliteHide
This section is currently hidden. Click the show button to view.
Formula:
SrB6O9(OH)2 · 3H2O
Colour:
Colourless, grayish white
Lustre:
Sub-Vitreous, Pearly
Crystal System:
Monoclinic
Name:
Named by R.C. Erd, V. Morgan, and J.R. Clark in 1961 in honor of George Gerard Tunell, Jr. (4 April 1900, Chicago, Illinois, USA - 4 July 1996, Montecito, California, USA), professor of geochemistry, University of California. President of the Mineralogical Society of America (1950) and Roebling Medal recipient in 1973. He made major advances in X-ray crystallography, physical chemistry, and thermodynamic analysis of minerals, especially metallic ores. The name is pronounced tŭn nĕl' īt.
This page provides mineralogical data about Tunellite.
Unique IdentifiersHide
This section is currently hidden. Click the show button to view.
Long-form identifier:
mindat:1:1:4050:7
2a258ab6-cf35-4a10-930b-f1d116d001a1
IMA Classification of TunelliteHide
This section is currently hidden. Click the show button to view.
Classification of TunelliteHide
This section is currently hidden. Click the show button to view.
6.FC.05
6 : BORATES
F : Hexaborates
C : Phyllo-hexaborates
26.6.6.2
26 : HYDRATED BORATES CONTAINING HYDROXYL OR HALOGEN
6 : Hexaborates
9.3.31
9 : Borates
3 : Borates of Ca and Sr
Mineral SymbolsHide
This section is currently hidden. Click the show button to view.
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference |
|---|---|---|
| Tnl | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of TunelliteHide
This section is currently hidden. Click the show button to view.
Comment:
Pearly on cleavages
Colour:
Colourless, grayish white
Cleavage:
Perfect
Perfect on {100}
Distinct on {001}
Density:
2.40(1) g/cm3 (Measured) 2.391 g/cm3 (Calculated)
Optical Data of TunelliteHide
This section is currently hidden. Click the show button to view.
RI values:
_n_α = 1.519 _n_β = 1.534 _n_γ = 1.569
δ = 0.050
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Optical Extinction:
Y = b; X ∧ a = 29°; Z ∧ c = –5°.
Chemistry of TunelliteHide
This section is currently hidden. Click the show button to view.
Mindat Formula:
SrB6O9(OH)2 · 3H2O
Crystallography of TunelliteHide
This section is currently hidden. Click the show button to view.
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Cell Parameters:
a = 14.415(3) Å, b = 8.213(1) Å, c = 9.951(2) Å
β = 114.05°
Ratio:
a:b:c = 1.755 : 1 : 1.212
Unit Cell V:
1,075.83 ų (Calculated from Unit Cell)
Morphology:
Crystals to 10 cm elongated on [001]. Flattened tabular with dominant {100}. Compact fine grained nodules. Forms include {100}, {001}, {110}, {011}, and {111}.
Crystal StructureHide
This section is currently hidden. Click the show button to view.
Load
Unit Cell |Unit Cell Packed
2x2x2 |3x3x3 |4x4x4
Show
Big Balls |Small Balls |Just Balls |Spacefill
Polyhedra Off |Si Polyhedra |All Polyhedra
Remove metal-metal sticks
Display Options
Black Background |White Background
Perspective On |Perspective Off
2D |Stereo |Red-Blue |Red-Cyan
View
CIF File Best |x |y |z |a |b |c
Rotation
Stop |Start
Labels
Console Off |On |Grey |Yellow
CIF Raw Data - click here to close
X-Ray Powder DiffractionHide
This section is currently hidden. Click the show button to view.
Image Loading
Radiation - Copper Kα
Data Set:
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 6.57 Å | (100) |
| 4.525 Å | (11) |
| 3.867 Å | (9) |
| 5.138 Å | (8) |
| 3.592 Å | (8) |
| 2.503 Å | (8) |
| 6.78 Å | (7) |
Comments:
Furnace Creek district, California, USA.
Geological EnvironmentHide
This section is currently hidden. Click the show button to view.
Geological Setting:
Secondary mineral in borate deposits
Type Occurrence of TunelliteHide
This section is currently hidden. Click the show button to view.
General Appearance of Type Material:
White compact fine-grained nodules. Also as individual long prismatic crystals up to 1.5 cm in length and equant crystals up to 1 cm in diameter.
Place of Conservation of Type Material:
National Museum of Natural History, Washington, D.C., USA, number 123928.
Geological Setting of Type Material:
A secondary mineral in a borate deposit.
Associated Minerals at Type Locality:
Other Language Names for TunelliteHide
This section is currently hidden. Click the show button to view.
Common AssociatesHide
This section is currently hidden. Click the show button to view.
Associated Minerals Based on Photo Data:
Related Minerals - Strunz-mindat GroupingHide
This section is currently hidden. Click the show button to view.
Other InformationHide
This section is currently hidden. Click the show button to view.
Notes:
Soluble in cold dilute acid or strong alkaline solutions. Unaffected by glycerol or methanol. In H2SO4, a coating of SrSO4 inhibits further dissolution.
Heated in a closed tube, tunellite exfoliates perpendicular to the cleavage, turns silvery white (resembling muscovite), then turns chalky white. The water driven off has a pH of 4.
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for TunelliteHide
This section is currently hidden. Click the show button to view.
References for TunelliteHide
This section is currently hidden. Click the show button to view.
Localities for TunelliteHide
This section is currently hidden. Click the show button to view.
This 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.
Locality ListHide
This section is currently hidden. Click the show button to view.
- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for references and further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. 
- Good crystals or important locality for species. 
- World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).
All localities listed without proper references should be considered as questionable.