Cleavage Collection

Cleavage Collection

  • Mineral Cleavage Educationa Collection


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1.50 lbs
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Cleavage is a readily recognizable property of some minerals and follows the internal crystal structure of that mineral. Terms used in a study of crystallography apply to the cleavage plans. 6 specimens approximately 1 1/2" x 1 1/2".

Cleavage is the tendency of minerals to break along preferred directions. Some minerals tend to have on direction of cleavage called pinacoidal cleavage. Some minerals cleave in two directions and this is referred to as prismatic cleavage. Minerals that have cleavage in three directions not at right angles have rhombohedral cleavage. If the cleavage is in three directions at right angles it is cubic cleavage. Cleavage in four directions is called octahedral cleavage.
1. Muscovite...Pinacoidal Cleavage
2. Feldspar....Prismatic Cleavage
3. Biotite.....Pinacoidal Cleavage
4. Spodumene...Prismatic Cleavage
5. Calcite.....Rhombohedral Cleavage
6. Halite......Cubic Cleavage
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  • Mineral Hardness Scale Ruler

    The Mineral Hardness Ruler is a stimulating visual aid, educates in one phase of mineralogy, and provides the standard ruler measurement scales needed in classes.

    Rockhounds, mineral enthusiasts, students, teachers, geologists, and any one interested in rocks and minerals will find the Mineral Hardness Ruler a handy visual aid for quick information on mineral hardness.

    The two-sided, flexible, glossy, vinyl ruler consists of five scales: three measurement scales and two mineral hardness scales. The measurement scales are in standard ruler measurements of tenths of inches, sixteenths of inches, and millimeters. Mohs' relative hardness numbers are integrated into the inch scales, while a separate scale exists for an absolute mineral hardness scale by Rosiwal.

    On one side of the ruler are pictures of the ten common minerals, in full color, selected by Mohs for his relative hardness scale. On the reverse side of the ruler are six common items with their relative hardnesses. These items, along with known minerals, can be used as a handy field kit to test the relative hardness of an unknown mineral.

    Hardness is one property of a mineral that can be used to distinguish among similar minerals. A given mineral can scratch any other mineral of the same or softer hardness. Over a hundred years ago, the German mineralogist Frederick Mohs devised the relative hardness scale that has found favor with mineralogists for over a century. Others, such as Rosiwal, formed absolute hardness scales using the same minerals as Mohs. For example, diamond, the hardest substance in Nature is not twice as hard as apatite, 10 versus 5, but over twenty thousand times as hard, 140,000 versus 6.5.

  • North American Rock Collection

    This collection with rock types and associations with the North American continent contains 50 specimens with each group represented: igneous, metamorphic, and sedimentary. Specimens are approximately 1" x 1",number coded in compartmented container.

    The current collection contains:
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    Granite-potassium-CO Rhyolite Porphyry-CO
    Pegmatite-CO Vitrophyre-CO
    Andesite-CO Vesicular Basalt-CO
    Tuff-CO Monzonite Porphyry-CO
    Granite-sodium-CO Basalt-CO
    Diorite-CO Granodiorite-CO
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    Pumice-CA Anorthosite-WY
    Carbonatite-QUE Scoria-CO
    Breccia-CO Trachyte-CO

    Coquina-TX Conglomerate- CO
    Siltstone-CO Sandstone-CO
    Rock Salt-UT Oil Shale-CO
    Limestone-CO Fossiiiferous Limestone-TX
    Bituminous Coal-WY Arkose-CO
    Gypsum-CO Shale-CO
    Breccia-CO Calcareous Tufa-SD
    Dolomite-CO Sandstone-banded-WY

    Gneiss-CO Slate-VT
    Mica Schist-WY Garnet Schist-SD
    Amphibolite-CO Homfels-WY
    Serpentinite-WY Quartzite -WY
    Phyllite-SD Anthracite Coal-PA
    Marble-WY Chlorite Schist-CO
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    BOTRYOIDAL -globular forms like a bunch of grapes CAPILLARY -hair like crystals
    COLLOFORM -spherical forms of radiating crystals COLUMNAR -column like crystal
    CONCENTRIC -spherical layers around a common center CONCRETION -minerals formed around a nucleus
    DENDRITIC -slender divergent branches DRUSY -a layer of small crystals on a surface
    FIBROUS -slender fiber aggregate of crystals FILIFORM -embedded threadlike crystals
    FOLIATED -easily separated into plates GEODE - a spherical hollow cavity lined by mineral(s)
    GLOBULAR -radiating crystals forming small spheres GRANULAR -composed of grain like crystals
    LAMELLAR -plate like crystals forming layers MAMMILLARY-round masses resembling mammae
    MASSIVE -a mineral w/o distinguishing features or form MICACEOUS -easily separated into thin sheets
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    RETICULATED -lattice like groups of crystals ROSETTE- a flowerlike crystal growth of minerals
    STALACTITIC-conical/cylindrical deposits of minerals STELLATED -radiating crystals forming circular groups

    1.  Calcite (in Limestone) Oolitic
    2.  Quartz Geode
    3.  Wavellite Radiated/Stellated
    4.  Barite Rosette
    5.  Vanadinite Drusy
    6.  Spodumene Columnar
    7.  Gypsum var. Satin Spar Fibrous
    8.  Biotite Micaceous/Foliated
    9.  Barite Lamellar/Tabular
    10. Olivine Granular
    11. Dolomite Granular
    12. Bauxite Pisolitic
    13. Onyx Banded
    14. Chalcedony Massive
    15. Gypsum var. Alabaster Massive
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    Glass plates for use in basic mineral identification. Minerals with a hardness of 6 or higher will scratch glass making a glass streak plate a handy tool for quick test to establish on which half of the hardness scale your specimen exists. Rocks and minerals that scratch glass, and do not have cracks and pits, are those that readily take a polish in a tumbler. 1 inch by 2 inch.

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