Calclacite

Formula:

Ca[Cl|CH

COO] · 5H

System:

Monoclinic

Colour:

White

Name:

In allusion to its composition, containing CALcium, chlorine (CL) and ACetate.

Calcium chloride acetate pentahydrate.

A mineral which forms on calcareous rock and fossil specimens and pottery shards through the interaction of acetic acid derived from oak museum storage cabinets (anthropogenic).

Classification of Calclacite

IMA status:

Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"

Explanation of status:

No genuinely natural occurrence documented. Found on specimens of limestone in wooden drawers.

Strunz 8th edition ID:

9/A.02-20

Nickel-Strunz 10th (pending) edition ID:

10.AA.25

10 : ORGANIC COMPOUNDS
A : Salts of organic acids
A : Formates, Acetates, etc.

Dana 8th edition ID:

50.2.4.1

50 : ORGANIC COMPOUNDS
2 : Mellitates, Citrates, Cyanates, Acetates and Formates

Hey's CIM Ref.:

31.4.1

31 : Oxalates, Citrates, Mellitates and Acetates
4 : Acetates

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Physical Properties of Calclacite

Lustre:

Silky

Diaphaneity (Transparency):

Translucent

Comment:

Lustre silky in aggregates.

Colour:

White

Comment:

Not determined

Density (measured):

1.5 g/cm³

Density (calculated):

1.55 g/cm³

Crystallography of Calclacite

Crystal System:

Monoclinic

Class (H-M):

2/m - Prismatic

Space Group:

P2₁/b {P1 1 2₁/b} {P2₁/c} {P1 2₁/c 1} {P2₁/a}

Cell Parameters:

a = 11.51Å, b = 13.72Å, c = 6.82Å
β = 116.7°

Ratio:

a:b:c = 0.839 : 1 : 0.497

Unit Cell Volume:

V 962.16 Å³ (Calculated from Unit Cell)

Morphology:

Crystals as slky, hairlike efflorescences.

Comment:

Space Group determined on synthetic material.

Optical Data of Calclacite

Type:

Biaxial (+)

RI values:

n_α = 1.468 n_β = 1.484 n_γ = 1.515

2V:

Measured: 80° , Calculated: 74°

Maximum Birefringence:

δ = 0.047

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

Surface Relief:

Moderate

Dispersion:

relatively weak

Chemical Properties of Calclacite

Formula:

Ca[Cl|CH

COO] · 5H

Essential elements:

C, Ca, Cl, H, O

All elements listed in formula:

C, Ca, Cl, H, O

Relationship of Calclacite to other Species

10.AA.05

Formicaite

Ca[HCOO]

10.AA.10

Dashkovaite

Mg[HCOO]

· 2H

10.AA.20

Acetamide

CONH

10.AA.30

Paceite

CaCu(CH

COO)

·6H

10.AA.35

Hoganite

Cu(CH

COO)

·H

Other Names for Calclacite

Other Languages:

German:	Calclacit
Spanish:	Calclacita

Other Information

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 Calclacite

Reference List:

van Tassel (1945) Musée royale d’histoire naturelle de Belgique, Bulletin: 21: 1.

American Mineralogist (1947): 32: 254.

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, 1124 pp.: 1107.

Van Tassel, R. (1958) On the crystallography of calclacite, Ca(CH3COO)Cl•5H2O. Acta Crystallographica: 11: 745–746.

Giuseppetti G., Tadini C., Ungaretti L. (1970) - La struttura cristallina della calclacite. Periodico di mineralogia – Roma, pp. 145-158.

Giuseppetti G., Tadini C., Ungaretti L. (1972) - La struttura cristallina di una fase triclina del composto corrispondente alla calclacite Ca(CH3COO)Cl*5H2O. Periodico di mineralogia – Roma: 9-21.