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Rio Gavottino, Casarza Ligure, Genova Province, Liguria, Italy
© D.Preite - M.C.
The structure of Bakerite is closely related to that of Datolite. Both minerals contain sheets of four- and eight-membered rings of corner-sharing (HBO4) and (SiO4) tetrahedra, classifying them as phyllo-borosilicates. In Datolite, (HBO4) and (SiO4) are alternating, whereas in Bakerite, one fourth of the (SiO4) tetrahedra is replaced by (HBO4), leading to a net formula of the anion of (H5Bi5Si3O20)n with (H5Bi5Si3O20) as the repeating unit. There is no evidence for even a partial subsitution of (SiO4) with (HBO4) in Datolite, thus making Bakerite a distinct species (Perchiazzi et al., 2004). Note that we are using a sum formula for the anion. It may also be written as (B5Si3O15(OH)5), indicating that the five protons are bonded to oxygen atoms.
Compare also the closely related Shimazakiite.
Classification of Bakerite
|IMA status:||Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"|
|Strunz 8th edition ID:||8/B.29-20|
|Nickel-Strunz 10th (pending) edition ID:||9.AJ.20|
9 : SILICATES (Germanates)
A : Nesosilicates
J : Nesosilicates with BO3 triangles and/or B, Be tetrahedra, cornersharing with SiO4
|Dana 8th edition ID:||54.2.1b.1|
54 : NESOSILICATES Borosilicates and Some Beryllosilicates
2 : Borosilicates and Some Beryllosilicates with B in  coordination
|Hey's CIM Ref.:||17.5.13|
17 : Silicates Containing other Anions
5 : Borosilicates
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Type Occurrence of Bakerite
|Type Locality:||Corkscrew Canyon Mine (Corkscrew Mine), Ryan, Furnace Creek District (Furnace Creek Borate District; Death Valley Area Borate Deposits; Ryan area), Inyo Co., California, USA|
|Year of Discovery:||1903|
|Associated Minerals at type locality:|
Occurrences of Bakerite
|Geological Setting:||Veins in altered volcanics.|
Physical Properties of Bakerite
|Density (measured):||2.88 g/cm3|
|Density (calculated):||2.94 g/cm3|
Crystallography of Bakerite
|Class (H-M):||2/m - Prismatic|
|Cell Parameters:||a = 4.85Å, b = 7.627Å, c = 9.659Å|
β = 90.255°
|Ratio:||a:b:c = 0.636 : 1 : 1.266|
|Unit Cell Volume:||V 357.29 Å³ (Calculated from Unit Cell)|
|Morphology:||Dense and microcrystalline, resembling unglazed porcelain. Nodules and veins. Stout rhombic prisms|
|X-Ray Powder Diffraction:|
Radiation - Copper Kα
Data courtesy of RRUFF project at University of Arizona, used with permission.
Optical Data of Bakerite
|RI values:||nα = 1.624 nβ = 1.635 nγ = 1.654|
|2V:||Measured: 87° to 88°|
|Maximum Birefringence:||δ = 0.030|
Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Chemical Properties of Bakerite
|Simplified for copy/paste:||Ca4(H5B5Si3O20)|
|Essential elements:||B, Ca, H, O, Si|
|All elements listed in formula:||B, Ca, H, O, Si|
Relationship of Bakerite to other Species
|Member of:||Gadolinite-Datolite Group|
|Other Members of Group:|
|Related Minerals - Nickel-Strunz Grouping):|
|Related Minerals - Hey's Index Grouping:|
Other Names for Bakerite
|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 Bakerite
Giles, W.B. (1903), Bakerite (a new borosilicate of calcium) and howlite from California, Mineralogical Magazine: 13: 353-355.
Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II. John Wiley and Sons, Inc., New York, 7th edition, revised and enlarged: 363.
Kramer, H.C. & R.D. Allen (1956), A restudy of bakerite, priceite, and veatchite, American Mineralogist: 41: 689-700.
Murdoch, Joseph (1962), Bakerite crystals: American Mineralogist: 47: 919-923.
Pemberton, H. Earl (1971a) Type locality for bakerite. American Mineralogist: 56: 1109-1110.
Perchiazzi, N., Gualtieri, A.F., Merlino, S., Kampf, A.R. (2004): The atomic structure of bakerite and its relationship to datolite. The American Mineralogist, 89, 767-776.
Internet Links for Bakerite
Localities for Bakerite
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.