Calcite

Calcite

Calcite in all its aspects‣ Text: Ludo Van Goethem‣Calcite samples:‣ Hugo en Paul Bender‣ Frans Bollaerts‣ Gust Boxtaens‣ Axel Emmermann‣ Jan Jensen‣ Jef Leybaert‣ Paul Van hee‣ Ludo Van Goethem‣ Albert Vercammen‣ Fons Quadens© MKA 2006

Calcite in all its aspects:References‣Illustrations of slides:‣ 10: Inleiding tot de geologie en geomorfologievan België, D. Goossens 1984‣ 11: Maps: Earth, Past & present, Thompson etal, Harcourt Brace Coll Pub, 1995; Graph:www.globalwarmingart.com‣ 13: Guide to TL Date Measurement,www.users.globalnet.uk/~qtls‣ 35, 82: Mineralogy and Petrology course 2050,October 2004‣ 61: Schweizer Strahler Vol 6, 4, 1982© MKA 2006

ChocolatesBeerCichoreeSproutsCalcite© MKA 2006

AreBelgianSpecialities© MKA 2006

Calcite‣ What is Calcite ?‣ Crystal structure‣ Calcite in Belgium‣ Fluorescence‣ Crystal shapes‣ Twinning‣ Paragenesis‣ Special effects

Double refractionTwo polarisationdirections of lighthave a differentrefractive index.

Calcite: Strukture‣ Trigonal‣ Cleavage: rhombohedron {10 -11}: perfekt‣ trifold axis: 3 cleavage planes, NOT 6 !!! aid to identification of forms‣ many crystal forms (more than 2000 !!!) direct/positive forms (follow cleavage planes) indirect/negative forms (between cleavage planes)

Calcite in Belgium‣ Mainly in limestone Devonian en Carboniferous‣ Calcite age: not really known

Belgium in the Paleozoïcum‣ Tropics (Belgium = red dot)‣ High sealevels‣ See = CO2 removal‣ Marine lime deposits

Age Belgian Calcite‣ Not studied‣ Dating difficult and expensiveU/Pb methodSr-dating‣ Two processes:Hydrothermal (see paragenesis later)Hercynian folding periodEx Fluorite BeezKarst systemsFree groing in clayEx Couillet

Calcite age‣ Thermoluminescence at 275 °C radioactive damage‣ not the standard yellow fluorescence organic nature (right >>>)‣ Dating cave Calcite‣ 20 – 300 kJr

Fluorescence in Calcite‣ Main activator in Calcite: Mn 2+‣ Orange-red fluorescence around 615 nm‣ Also in other carbonates, Ex Aragonite‣ Extra players:‣ Fe: Fluorescence killer‣ Pb, Tl, Ce: Fluorescence activators‣ Others:‣ UO 2 with e-h pair: green fluorescence‣ Pb 2+ : blue-green fluorescence at 480 nm‣ RE 2+/3+‣ Organic compounds: yellow fluorescence Karst Calcites

UV-AMn 2+ -fluorescenceHuanzala, PeruUV-C

Calcite: crystal forms‣ Basal face / prism (often together)‣ Rhombohedron‣ Skalenohedron (NOT a piramid !!)‣ Isocelohedron (bipiramid)

Calcite: prism‣ Rare in Belgium‣ Mainly high temperature and ore deposits‣ Basal plane: very rare in belgiumPrism en basal plane on quartzSt-Austell, Cornwall, EngelandPrism andobtuse rhombohedronResteigne, Luxembourg

asal face +prismCharcas, MexicoUV-AVisible lightUV-B

asal face with central rhombohedronDalnegorsk, Russia

PrismIdar-Oberstein,GermanyUV-B

Prism with basal faceOld Yuma mine, Arizona, USAUV-BUV-A

Calcite: Rhombohedron‣ 6 faces: 3 upper, 3 lower‣ edge below face‣ direct: cleavage plane removes pieceout of face‣ indirect: cleavage plane removes pieceout of edge‣ many forms: oblique obtuse

Oblique RhombohedronBeez, Namur

Oblique Rhombohedron, fluorescenceUV-BBeez, Namur

Rhombohedron, fluorescence (UV-C)Beez, Namur

Etched RhombohedronBeez, Namur

Rhombohedron, fluorescence (UV-A)Huanzala, Peru

Indirect Rhombohedron(Cleavage plane on edge)Beez, Namur

Calcite Rose (Indirect Rhombohedron),St-Géry, Lot, Frankrijk

Obtuse Rhombohedron and prismNamêche, Namur

Oblique Rhombohedron, clear (left) andwith MnO2 colouration (right)Jemelle, Luxembourg

Prismatic growth of obtuse rhombohedronsRio Grande do Sul, Brazil

Very oblique and obtuseRhombohedronGourdinne, Namur

Rhombohedron, fluorescence (UV-A)Rio Grande do Sul, Brazil

Rhombohedron with DolomiteNamêche, NamurAt lowtemperaturesthere isalways theformation ofpure Dolomiteand Calcite(see phasediagram)

Rhombohedron, fluorescence (UV-A)Mont-sur-Marchienne

Calcite: Skalenohedron‣ 12 faces: 6 upper, 6 lower‣ edge below edge‣ alternating oblique and obtuse angles between faces‣ obtuse angle upper oblique angle lower part‣ direct and indirect forms

SkalenohedronBeez, Namur

Skalenohedron groupBeez, Namur

Parallel growth of SkalenohedronsBeez, Namur

Parallel growth of SkalenohedronsMont-Sur-Marchienne, Hainaut

Skalenohedron on QuartzMont-Sur-Marchienne, Hainaut

Etched Skalenohedron faceMont-Sur-Marchienne, Hainaut

Skalenohedron, fluorescence (UV-A)Beez, Namur

Skalenohedron, fluorescence (UV-A)Cavnic, Rumenia

Calcite: complex forms‣ All combinations of Rhombohedron Skalenohedron Prism‣ Belgian specialty‣ You can take a break here and drink a Belgianbeer or eat a Belgian chocolate

Pseudo “Dodecahedron”Combination of obtuse and very oblique RhombohedronMont-Sur-Marchienne, Hainaut

Prism en oblique RhombohedronMont-Sur-Marchienne, Hainaut

Skalenohedron withoblique Rhombohedron and prismCouillet, Hainaut

Prism, Skalenohedron andRhombohedronMont-Sur-Marchienne, Hainaut

2 Skalenohedrons and RhombohedronLandelies, Hainaut

Round CalciteNamêche, Namur

Barrel-deformed SkalenohedronsBeez, Namur

Flat deformed SkalenohedronsChokier, Liège

Barrel-deformed prism and basal faceMt Rudny, Kazachstan, USSR

Skalenohedron and rombohedronPau, FranceWatch theinternaldoublerefraction ofedges

Botryoidal aggregateMagane, High Atlas, Morocco

DendriticaggregateCavnic, RumeniaUV-BUV-A

Calcite: isocelohedron‣ Rare‣ Bi-Piramid‣ NO SkalenohedronBrenk, Eifel, Germany

Calcite: twins‣ What: 2 intergrown crystals following a law‣ 4 types: rotation twin (180°) around c-axis (basal twin) 3 mirror twins follow a Rhombohedral law mirror (1 -1 0 2): wide butterfy twin mirror (2 -2 0 1): narrow butterfly twin mirror (1 0 -1 1): not in Belgium mechanical twinning (deformation)

Calcite: Basal twin‣ What: rotation twin (180°) around the trifold axis‣ Parallel en basal forms‣ Rhombohedron = edge above edge and v.v.‣ Skalenohedron: obtuse above obtuse angle and v.v.Compare thetricks withthe rules insinglecrystals

Single and twinned SkalenohedronBiesmerée, NamurSingle crystaltwin> twinline> concave angleCheck the recognition tricks for twins and single crystals

Skalenohedron and obliqueRhombohedronBeez, Namur

Skalenohedron, NO twinBeez, NamurFind out whythis is not atwinA split lineis notalways atwin

Skalenohedron and prismCouillet, Hainaut

Skalenohedron and prismMt-s-Marchienne, Hainaut

Rhombohedron and SkalenohedronGourdinne, Namur

Obtuse Rhombohedron and prismLandelies, Hainaut

Obtuse Rhombohedron and prismAgapovka, Z-Ural, Russia

Calcite: twin (1 -1 0 2)‣ What: wide winged butterflies‣ mirror operation on (1-1 0 2)‣ Cleavage planes point away from c-axes (rundown from mirror plane to outer edge)

Butterfly twinBeez, Namur

Deformed Skalenohedron,Beez, NamurUV-AUV-BUV-C

Butterfly twinBeez, NamurWatch the orientation ofthe cleavage plane inthe right crystal

Mechanical deformation twinMont-sur-Marchienne, Hainaut

Calcite: twin (2 -2 0 1)‣ What: steep twin, bishops miter‣ mirror operation on (2 -2 0 1)‣ Cleavage planes point towards the c-axes (runupwards from mirror plane to outer edge)

Bisshops mitter twinBeez, NamurWatch theorientation of thecleavage planes)

Steep butterfly twinLandelies, Hainaut

Butterfly- and miter twinPas de Calais, France

Calcite: twin (1 0 -1 1)‣ Not in Belgium‣ Cleavage plane parallel to twin planeBerner Land, SwitserlandCumbria, England

Calcite: Paragenesis‣ Mainly via hydrothermal solutions‣ Together with/before/after Calcite‣ Other carbonates‣ Sulfides‣ Fluorite‣ Quartz‣ Other

DolomiteNamêche, Namur

AragoniteResteigne, Luxembourg

AragoniteJemelle, Luxembourg

Aragonite, Calcite, fluorescence (UV-C)Jemelle, Luxembourg

Aragonite, Sicily, ItalyUV-LEDUV-CUV-AUV-B

Aragonite, Riches, HighAtlas, MoroccoUV-CUV-BUV-A

MarcassiteBeez, Namur

MarcassiteBeez, Namur

PyriteCouillet, Hainaut

Pink Dolomite, MarcassiteResteigne, Luxembourg

Pink dolomite, Chalcopyrite, MarcassiteResteigne, Luxembourg

ManganiteResteigne, Luxembourg

Fluorite, Dolomite, QuartzBeez, Namur

FluoriteBeez, Namur

FluoriteMt-s-Marchienne, Hainaut

UV-AFluoriteHunan ,ChinaUV-B

QuartzMt-s-Marchienne, Hainaut

Barite,Beez, Namur

CerussiteJemelle, Luxembourg

Calcite: Special effects

Children’s headBeez, Namur

Calcite monsterBeez, Namur

Butterfly tieBeez, Namur

Vegetable gardenMt-s-Marchienne, Hainaut

CatMt-s-Marchienne, Hainaut

Quartz dollMt-s-Marchienne,Hainaut

Quartz poodleFleurus, Hainaut

Elf seatsAntoing, Hainaut

Belgian Christmas Ore (UV-C)Calcite with HydrozincitePlombières (Bleiberg), Liège

Powder sugarAntoing, Hainaut

PipesChokier, Liège

DiademeCavnic, Rumenia

Fluorescent turtle (UV-B),Mont-sur-Marchienne, Hainaut

The end