Garnet Classification
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Questions and Answers

What is the name of the grossular species that has a transparent orange to cinnamon-colored variety?

  • Tsavorite
  • Rhodolite
  • Demantoid
  • Hessonite (correct)
  • Which of the following is a characteristic of garnet and spinel?

  • Singly refractive (correct)
  • Pleochroic
  • Triply refractive
  • Doubly refractive
  • What is the most valuable red garnet?

  • Almandine
  • Spessartine
  • Pyrope
  • Rhodolite (correct)
  • What is the primary source of rhodolite since the 1960s?

    <p>East Africa</p> Signup and view all the answers

    What is the color of tsavorite?

    <p>Green with a slight amount of blue</p> Signup and view all the answers

    What is the coloring agent of color-change garnets?

    <p>Vanadium</p> Signup and view all the answers

    What is the variety of andradite that is colored by a mixture of chromium and iron?

    <p>Demantoid</p> Signup and view all the answers

    What is the characteristic of many garnets?

    <p>They are mixtures of two or more garnet species</p> Signup and view all the answers

    Why are huge numbers of dark-toned, reddish brown, calibrated pyrope-almandine garnets used in inexpensive, mass-market jewelry?

    <p>They are abundant and inexpensive</p> Signup and view all the answers

    What is the origin of tsavorite?

    <p>East Africa</p> Signup and view all the answers

    What is the reason cutters do not need to consider pleochroism when working with garnet and spinel?

    <p>They are singly refractive.</p> Signup and view all the answers

    What is the common characteristic of most red garnets, including rhodolite?

    <p>They are mixtures of pyrope and almandine.</p> Signup and view all the answers

    What is the primary characteristic used to classify garnets?

    <p>Optical and physical properties.</p> Signup and view all the answers

    What is the significance of East Africa in the context of rhodolite?

    <p>It is the primary source of rhodolite since the 1960s.</p> Signup and view all the answers

    Why are tsavorite and color-change garnets valuable?

    <p>Tsavorite is colored by vanadium, and color-change garnets are pyrope-spessartine mixtures.</p> Signup and view all the answers

    What is the significance of spinel in the history of gemology?

    <p>Historically important red gems, long identified as ruby, were recognized as spinel in the 1800s.</p> Signup and view all the answers

    What is the characteristic of demantoid?

    <p>It is the transparent green variety of andradite, colored by a mixture of chromium and iron.</p> Signup and view all the answers

    Why are pyrope-almandine garnets used in inexpensive, mass-market jewelry?

    <p>Huge numbers of dark-toned, reddish brown, calibrated pyrope-almandine garnets are available.</p> Signup and view all the answers

    Study Notes

    Garnet

    • Hessonite is a transparent orange to cinnamon-colored variety of the grossular species of garnet.
    • Garnet is singly refractive, eliminating the need for cutters to consider pleochroism.
    • Most red garnets, including the popular rhodolite, are mixtures of pyrope and almandine.
    • Rhodolite is the most valuable red garnet, characterized by a dark purplish red to light reddish purple hue.
    • Garnets can be a mixture of two or more garnet species.
    • Gemologists classify garnets by their physical and optical properties.

    Spinel

    • Historically, many red gems identified as ruby were recognized as spinel in the 1800s.

    Tsavorite

    • Tsavorite is a type of garnet colored by vanadium, with the best quality being pure green or green with a slight amount of blue.
    • Tsavorite is mostly mined in East Africa.
    • Large tsavorite rough is extremely rare, resulting in a significant increase in value between small and large fashioned stones.

    Demantoid

    • Demantoid is the transparent green variety of andradite, colored by a mixture of chromium and iron.

    Garnet Trade

    • East Africa has been the most important source of rhodolite since the 1960s.
    • Many dealers sell garnets based on color or origin, rather than physical and optical properties.
    • Huge numbers of dark-toned, reddish brown, calibrated pyrope-almandine garnets are used in inexpensive, mass-market jewelry.

    Garnet

    • Hessonite is a transparent orange to cinnamon-colored variety of the grossular species of garnet.
    • Garnet is singly refractive, eliminating the need for cutters to consider pleochroism.
    • Most red garnets, including the popular rhodolite, are mixtures of pyrope and almandine.
    • Rhodolite is the most valuable red garnet, characterized by a dark purplish red to light reddish purple hue.
    • Garnets can be a mixture of two or more garnet species.
    • Gemologists classify garnets by their physical and optical properties.

    Spinel

    • Historically, many red gems identified as ruby were recognized as spinel in the 1800s.

    Tsavorite

    • Tsavorite is a type of garnet colored by vanadium, with the best quality being pure green or green with a slight amount of blue.
    • Tsavorite is mostly mined in East Africa.
    • Large tsavorite rough is extremely rare, resulting in a significant increase in value between small and large fashioned stones.

    Demantoid

    • Demantoid is the transparent green variety of andradite, colored by a mixture of chromium and iron.

    Garnet Trade

    • East Africa has been the most important source of rhodolite since the 1960s.
    • Many dealers sell garnets based on color or origin, rather than physical and optical properties.
    • Huge numbers of dark-toned, reddish brown, calibrated pyrope-almandine garnets are used in inexpensive, mass-market jewelry.

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    Description

    Learn about the classification of garnets, including their species and characteristics. Discover the differences between various types of garnets, such as rhodolite and pyrope.

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