Practice For Exam 1

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Test Yourself   pretty tacky, eh?

This is part of an old 1st hour exam, adapted to provide instant feedback. Select an answer by clicking a button. Learn from your mistakes and see what you know!  Your responses are not being recorded, nor is your identity known.  For best results, let the feedback window close (or close it yourself) before selecting a new answer.

  1. The extreme hardness of diamond is explained by

    all atoms being bonded covalently.
    a lack of cleavage.
    a conchoidal fracture pattern.
    chemical composition; carbon atoms are very difficult to scratch.

  2. If gemstone A is the same size, shape (cut) and weight as gemstone B then we may conclude that

    a) gemstone A and B are the same materials.
    b) gemstone A and B have the same specific gravity.
    c) gemstone A is an imitation of gemstone B.
    d) they are both of equivalent value.
    e) a and b.

  3. If cubic zirconia has a higher specific gravity than that of diamond, then identically cut and faceted diamond and cubic zirconia gemstones will

    weigh the same amount because they are cut the same.
    weigh different amounts; the diamond will be heavier.
    weigh different amounts; the cubic zirconia will be heavier.
    weigh different amounts, but which is heavier will depend on how big they are.
    weigh the same amount because they have very similar physical properties.

  4. Crystalline materials differ from amorphous materials by

    a) containing different chemical elements.
    b) having periodic spacing of atoms.
    c) being natural rather than man-made.
    d) a and b.
    e) all of the above.

  5. Step-cut gemstones can be distinguished from brilliant-cut gemstones by

    the shapes of the facets.
    the size of the table.
    whether the crown is domed or flat.
    the strength of the play-of-color.
    the number of facets; brilliant cuts have more facets than step cuts.

  6. Conchoidal fracture is

    common in minerals that contain 2 cleavages.
    common in minerals that contain 1 cleavage.
    common in minerals that do not have a cleavage.
    a fracture pattern that looks like splintered wood.
    restricted to minerals that have high specific gravities.

  7. Cleavage and parting are two physical properties that affect a gem or mineral's

    a) toughness
    b) hardness
    c) durability
    d) a and c
    e) all of the above.

  8. A Mohs hardness of 7 is often considered the minimum for jewelry gemstones because softer gems

    a) break too easily.
    b) can't be polished.
    c) are too easily scratched.
    d) a and c
    e) all of the above.

  9. Which of the following is correctly arranged by hardness?

    Corundum, topaz, orthoclase, quartz
    Fluorite, orthoclase, quartz, topaz.
    Quartz, corundum, topaz, diamond.
    Diamond, corundum, quartz, topaz.
    Talc, gypsum, fluorite, calcite.

  10. A gemstone that floats on top of a heavy liquid has a specific gravity that is

    the same as the liquid.
    greater than the liquid.
    less than the liquid.
    greater than or less than the liquid, depending on size of the gemstone.
    none of the above

  11. A mineral's luster is a physical property that depends on the

    diffraction of light from the mineral's surface.
    the reflection of light from the minerals surface.
    the absorption of different wavelengths of light at the minerals surface.
    the presence or absence of a chromophore.
    the emission of light after some light is absorbed.

  12. Asterism is caused by

    the presence of more than one chromophore.
    randomly arranged, reflective mineral inclusions.
    color centers.
    diffraction in more than one direction.
    none of the above

  13. Tiger's eye or gems that display a cat's eye exhibit a phenomenon called

    none of the above

  14. To see the green color in an emerald, the Cr present must absorb the

    green part of the visible spectrum.
    yellow part of the visible spectrum.
    red part of the visible spectrum.
    blue part of the visible spectrum.
    part of the infrared spectrum.

  15. Gem labradorite feldspar and opal owe their unique color displays to

    color centers.
    transition metal chromophores.

  16. Play-of-color is a term used to describe

    different colors caused by many different chromophores.
    the difference between hue and tone.
    flashes of color in opal.
    aventurescence in sunstone.
    a particularly vibrant Broadway show.

  17. Aventurescence is a phenomenon caused by

    reflective mineral inclusions.
    fluorescence in moonstone.
    color centers.
    none of the above

  18. Fluorescence of a gem in ultraviolet light is a result of

    the emission of ultraviolet light.
    the absorption of visible light.
    the absorption of ultraviolet light and the emission of visible light.

  19. Color in allochromatic minerals and gems is

    a diagnostic property that can aid in mineral or gem identification.
    caused by chromophores that are present in great abundance.
    not a diagnostic property for identification purposes.
    caused by reflection from randomly arranged mineral inclusion.
    none of the above.

  20. Color centers are the source of color in minerals that

    contain transition elements.
    are ideochromatic.
    are capable of diffracting light.
    contain crystal lattice defects.
    are fluorescent.

  21. Absorption of light by chromophores to produce color occurs

    within the nucleus of the chemical element that is the chromophore.
    by moving a proton from one type of orbital to another.
    when atoms can move from one site to another within a crystal, absorbing energy.
    by the movement of electrons.
    by diffraction.

  22. Transition elements are uniquely suited to act as chromophores because they

    contain electrons in partially filled d-orbitals.
    are electrically neutral.
    are the most common elements in nature.
    are highly mobile in crystals.
    all of the above.

  23. A gem or mineral that is red absorbs

    red light.
    mostly red light.
    most wavelength of the visible spectrum except red.
    more of the visible spectrum than a gem or mineral that is violet.
    less of the visible spectrum than a colorless gem.

  24. Gems and minerals whose color can be altered by high energy forms of radiation are colored by

    color centers
    transition elements
    none of the above

  25. In crystallography, a form is defined as

    the habit of the mineral.
    a group of symmetrically related crystal faces.
    a group of crystal faces with adjoining edges.
    a specific type of symmetry element.
    an incomplete crystal.

  26. The internal arrangement of atoms in crystalline materials is reflected in the external shapes of crystals by

    the angles between crystal faces.
    the symmetry of crystal faces.
    the shape of the smallest, imaginary "building block" needed to construct the crystal.
    all of the above.

  27. The symmetry of crystal faces with respect to a line, plane and/or point can be used to classify crystals into

    crystal habits.
    closed or open crystal forms.
    crystal interfacial angles.
    crystal systems.
    none of the above.

  28. The hexagonal crystal system differs from all others in being composed of a unit cell that

    has 4 imaginary axes.
    has a long c-axis.
    is smaller than all the others.
    has sides that are not at right angles.
    has 6 faces.

  29. The isometric (cubic) crystal system has having

    3 crystallographic axes of equal length.
    4 crystallographic axes of unequal length.
    no crystallographic axes perpendicular.
    no crystallographic axes of equal length.
    3 crystallographic axes of unequal length.

  30. Minerals that form crystals that fall within the tetragonal crystal system can

    also form crystals of the isometric system.
    grow crystals of different shapes, but all the crystals will have symmetries of the tetragonal system.
    also form crystal that have symmetries appropriate to any of the crystal systems.
    show nearly an infinite variety of symmetries.
    have only a center of symmetry.

  31. Most common gem minerals are members of the

    isometric, tetragonal and hexagonal crystal systems
    monoclinic and triclinic systems
    orthorhombic and isometric systems
    isometric system
    orthorhombic system

  32. Prism and pinacoids are types of

    open forms
    crystalline solids
    symmetry operators
    crystallographic axes
    closed forms

  33. Hue is the term used to describe the

    amount of brown or gray present in a color
    vibrancy of a color
    color present (red, blue, green, etc.)
    darkness or lightness of the color
    none of the above.

Updated 08/22/16
Comments and questions to
Department of Geological Sciences
The University of Texas at Austin