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Ghiaraite

A valid IMA mineral species

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Maria Rosaria Ghiara (b. 1948)

Formula:

CaCl₂ · 4H₂O

Specific Gravity:

1.838 (Calculated)

Crystal System:

Triclinic

Name:

In honor of Maria Rosaria Ghiara (b. 1948) who is Head of Real Museo Mineralogico of Napoli and Centro Musei delle Scienze Naturali e Fisiche dell’Università degli Studi di Napoli Federico II. Several years ago Ghiara began a program to promote scientific collaborations to obtain new information about the stored minerals from the Vesuvius volcano in the last 200 years.

Type Locality:

ⓘ Mount Vesuvius, Somma-Vesuvius Complex, Naples, Campania, Italy

Known synthetic compound. The type sample was collected at the Vesuvius volcano, stored in a sealed glass vial and deposited at the Real Museo di Napoli in 1872 by Arcangelo Scacchi. The combination of small grain size plus sensitivity to the moisture did not allow a better physical or optical characterization.

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Unique IdentifiersHide

Mindat ID:

43592

Long-form identifier:

mindat:1:1:43592:9

GUID
(UUID V4):

2bdb7730-29bc-49e0-8ba2-64a2604350f6

IMA Classification of GhiaraiteHide

IMA status:

Approved

Classification of GhiaraiteHide

Strunz-mindat (2024):

3.BB.40

3 : HALIDES
B : Simple halides, with H₂O
B : M:X = 1:2

Mineral SymbolsHide

As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

Symbol	Source	Reference
Ghi	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 GhiaraiteHide

Density:

1.838 g/cm³ (Calculated)

Optical Data of GhiaraiteHide

Type:

Biaxial (-)

RI values:

n_α = 1.530 n_β = 1.557 n_γ = 1.567

Max Birefringence:

δ = 0.037

Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.

Surface Relief:

Low

Comments:

From synthetic material

Chemistry of GhiaraiteHide

Mindat Formula:

CaCl₂ · 4H₂O

Elements listed:

Ca, Cl, H, O - search for minerals with similar chemistry

Crystallography of GhiaraiteHide

Crystal System:

Triclinic

Class (H-M):

1 - Pinacoidal

Space Group:

Cell Parameters:

a = 6.3660 Å, b = 6.5914 Å, c = 8.5568 Å
α = 93.504°, β = 97.778°, γ = 110.557°

Ratio:

a:b:c = 0.966 : 1 : 1.298

Unit Cell V:

330.80 Å³ (Calculated from Unit Cell)

Crystal StructureHide

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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure

ID	Species	Reference	Link	Year	Locality	Pressure (GPa)	Temp (K)
0020228	Ghiaraite	Thewalt U, Bugg C E (1973) Crystal structure of calcium chloride tetrahydrate Acta Crystallographica B29 615-617		1973	synthetic	0	293
0019787	Ghiaraite	Leclaire A, Borel M M (1979) Liaisons hydrogene et coordination du calcium dans les cristaux de CaCl24H2O alpha* Acta Crystallographica B35 585-588		1979	synthetic	0	293

CIF Raw Data - click here to close

data_global
_chemical_name_mineral 'Ghiaraite'
loop_
_publ_author_name
'Thewalt U'
'Bugg C E'
_journal_name_full 'Acta Crystallographica, Section B'
_journal_volume 29 
_journal_year 1973
_journal_page_first 615
_journal_page_last 617
_publ_section_title
;
 Crystal structure of calcium chloride tetrahydrate
;
_database_code_amcsd 0020228
_chemical_compound_source 'Synthetic'
_chemical_formula_sum 'Ca Cl2 O4'
_cell_length_a 6.593
_cell_length_b 6.364
_cell_length_c 8.557
_cell_angle_alpha 97.77
_cell_angle_beta 93.52
_cell_angle_gamma 110.56
_cell_volume 330.776
_exptl_crystal_density_diffrn      1.757
_symmetry_space_group_name_H-M 'P -1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '-x,-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
Ca   0.11880  -0.01400   0.26150
Cl1   0.29100  -0.27770   0.05040
Cl2  -0.24950  -0.23930   0.41300
O1  -0.18230  -0.18710   0.04340
O2  -0.01520   0.28950   0.27150
O3   0.47880   0.24090   0.26630
O4   0.24930  -0.25090   0.41540
loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_22
_atom_site_aniso_U_33
_atom_site_aniso_U_12
_atom_site_aniso_U_13
_atom_site_aniso_U_23
Ca 0.02323 0.01836 0.02981 0.00182 0.00105 -0.00351
Cl1 0.02818 0.02238 0.02370 0.00493 0.00418 -0.00050
Cl2 0.02399 0.02220 0.02658 -0.00274 0.00209 -0.00251
O1 0.02685 0.02342 0.03915 0.00146 0.00261 -0.00551
O2 0.03446 0.02238 0.03268 0.00784 -0.00183 0.00175
O3 0.03256 0.02884 0.02837 -0.00438 0.00837 -0.00601
O4 0.03503 0.02692 0.02909 0.01040 0.00105 -0.00226

X-Ray Powder DiffractionHide

Powder Diffraction Data:

d-spacing	Intensity
6.124 Å	(47)
5.874 Å	(73)
4.600 Å	(88)
3.569 Å	(46)
2.939 Å	(77)
2.717 Å	(88)
2.628 Å	(100)
2.204 Å	(75)

Comments:

From Type Description.

Geological EnvironmentHide

Paragenetic Mode(s):

Paragenetic Mode	Earliest Age (Ga)
Stage 7: Great Oxidation Event	<2.4
45b : [Other oxidized fumarolic minerals]

Type Occurrence of GhiaraiteHide

Type Locality:

ⓘ Mount Vesuvius, Somma-Vesuvius Complex, Naples, Campania, Italy

General Appearance of Type Material:

Euhedral isometric very small grains (up to 5–6 μm long) intimately intermixed with chlorocalcite.

Place of Conservation of Type Material:

Reale Museo of Napoli, Napoli, Italy, registration number 16986E5525

Geological Setting of Type Material:

Mount Vesuvius, Italy in voids in the ejecta surface that were exposed to volcanic vapors.

Associated Minerals at Type Locality:

Synonyms of GhiaraiteHide

IMA2012-072

Related Minerals - Strunz-mindat Grouping Hide

3.BB.05	Eriochalcite	CuCl₂ · 2H₂O	Orth. mmm (2/m 2/m 2/m) : Pmna
3.BB.10	Rokühnite	FeCl₂ · 2H₂O	Mon.
3.BB.15	Bischofite	MgCl₂ · 6H₂O	Mon. 2/m : B2/m
3.BB.20	Nickelbischofite	NiCl₂ · 6H₂O	Mon. 2/m
3.BB.25	Sinjarite	CaCl₂ · 2H₂O	Tet.
3.BB.30	Antarcticite	CaCl₂ · 6H₂O	Trig. 3 2 : P3 2 1
3.BB.35	Aravaipaite	Pb₃AlF₉ · H₂O	Tric. 1 : P1
3.BB.35	Tachyhydrite	CaMg₂Cl₆ · 12H₂O	Trig. 3 : R3

Other InformationHide

Special Storage/
Display Requirements:

strongly deliquescent when exposed to the air

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 GhiaraiteHide

mindat.org URL:

https://www.mindat.org/min-43592.html
Please feel free to link to this page.

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External Links:

Look for Ghiaraite on Webmineral

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Raman and XRD data at RRUFF project

References and PDF downloads at RRUFF project

American Mineralogist Crystal Structure Database

Handbook of Mineralogy page PDF

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References for GhiaraiteHide

Reference List:

Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2013) IMA Commission on New Minerals, Nomenclature and Classification. CNMNC Newsletter No. 15. Mineralogical Magazine, 77 (1) 1-12 doi:10.1180/minmag.2013.077.1.01

Rossi, M., Nestola, F., Zorzi, F., Lanza, A., Peruzzo, L., Guastoni, A., Kasatkin, A. (2014) Ghiaraite: A new mineral from Vesuvius volcano, Naples (Italy) American Mineralogist, 99 (2) 519-524 doi:10.2138/am.2014.4600

(2023) Ghiaraite. Handbook of Mineralogy. Mineralogical Society of America

Localities for GhiaraiteHide

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 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.


Italy (TL)
Campania Naples Somma-Vesuvius Complex ⓘ Mount Vesuvius (TL)	Williams et al. (2013) +1 other reference

Russia
Udmurt Republic Votkinsky District ⓘ Gremikhinskoye oil field (Gremikhinskoe oil field)	webmineral.ru (n.d.)