Chalcedony - General Over View
47 Questions
11 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is a common cut for Fire Agate?

  • Cabochon
  • Unique Cabochons (correct)
  • Carved
  • Beveled

    • What is a trade name for Chrysoprase from Africa?

  • Aquamarine
  • Blue Onyx
  • Southern Red Agate
  • Aquaprase (correct)

    • Where is Chrysocolla-in-chalcedony commonly found?

  • Queensland, Australia
  • US Keystone Copper Mine near Globe, Arizona (correct)
  • Brazil
  • Madagascar

    • What is often mistaken for true Moonstone?

    <p>Blue Chalcedony</p> Signup and view all the answers

    What is a common country of origin for Carnelian and Sard?

    <p>All of the above</p> Signup and view all the answers

    What is a common imitation material for Blue Chalcedony?

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

    What is a major manufacturer of chalcedony cameos and carvings?

    <p>Idar-Oberstein, Germany</p> Signup and view all the answers

    Where is Chinese Red Agate commonly found?

    <p>Southern China</p> Signup and view all the answers

    What is the Mohs scale of Chalcedony?

    <p>7</p> Signup and view all the answers

    What is the chemical composition of Chalcedony?

    <p>Silicon and oxygen</p> Signup and view all the answers

    What type of rocks can Chalcedony form in?

    <p>Pegmatite and volcanic and sedimentary rocks</p> Signup and view all the answers

    What is the formation process of Agate?

    <p>It forms inside gas cavities in volcanic rocks</p> Signup and view all the answers

    What is the characteristic of Chalcedony's crystal structure?

    <p>It is an aggregate of tiny microscopic crystals</p> Signup and view all the answers

    What is the phenomenon observed in Iris Agate?

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

    What is the characteristic of Fire Agate's crystal growth?

    <p>It forms as a botryoidal growth</p> Signup and view all the answers

    What is the common treatment for Blue Chalcedony?

    <p>Dyeing to create a deeper blue</p> Signup and view all the answers

    What is the characteristic of Chrysoprase's color?

    <p>It is a variable yellowish green to blue-green</p> Signup and view all the answers

    What happens when Chrysoprase is heated or exposed to sunlight?

    <p>Its color fades</p> Signup and view all the answers

    What is the primary source of Agate formation?

    <p>Gas cavities in volcanic rocks</p> Signup and view all the answers

    In which type of rocks can Chalcedony form?

    <p>Sedimentary and volcanic rocks</p> Signup and view all the answers

    What is the characteristic of Fire Agate's formation?

    <p>It forms as a botryoidal growth made up of flat crystals</p> Signup and view all the answers

    Which of the following is a country of origin for Chrysoprase?

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

    What is the primary source of Iris Agate?

    <p>Mexico and the US</p> Signup and view all the answers

    Where is Onyx and Sardonyx commonly found?

    <p>Brazil, Madagascar, and the US</p> Signup and view all the answers

    What is the origin of Chinese Red Agate?

    <p>Southern China, including Yunnan and Sichuan provinces</p> Signup and view all the answers

    Which of the following is a country of origin for Carnelian and Sard?

    <p>Brazil, India, and Uruguay</p> Signup and view all the answers

    What is the primary source of Fire Agate?

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

    Where is Blue Chalcedony commonly found?

    <p>California, US, and Namibia</p> Signup and view all the answers

    What is the origin of Treated Black Chalcedony?

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

    Which type of chalcedony is often cut into unique cabochons?

    <p>Fire Agate</p> Signup and view all the answers

    What is the trade name for Bluish Green Chrysoprase from Africa?

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

    Where is Chrysoprase commonly found?

    <p>In several countries including Australia, Brazil, and India</p> Signup and view all the answers

    What is often mistaken for true Moonstone?

    <p>Blue Chalcedony</p> Signup and view all the answers

    What type of chalcedony is often carved on a small and large scale?

    <p>Chinese Red Agate</p> Signup and view all the answers

    What type of chalcedony is often cut into cabochons or beads?

    <p>Treated Black Chalcedony</p> Signup and view all the answers

    What type of chalcedony is often sliced or carved into designs?

    <p>Iris Agate</p> Signup and view all the answers

    What type of chalcedony is often carved into cameos and carvings?

    <p>Onyx and Sardonyx</p> Signup and view all the answers

    What is the typical color range of Chalcedony in its purest form?

    <p>White to milky gray</p> Signup and view all the answers

    Which type of Chalcedony is known for its intense red, white, or grayish color bands?

    <p>Chinese Red Agate</p> Signup and view all the answers

    What is the characteristic of Chrysoprase's color when exposed to sunlight or heat?

    <p>Fades to a lighter shade</p> Signup and view all the answers

    Which type of Chalcedony displays semitransparent to translucent and iridescent colors?

    <p>Iris Agate</p> Signup and view all the answers

    What is the characteristic of Carnelian and Sard's color range?

    <p>Semitransparent to translucent and ranges from yellowish orange to brownish orange</p> Signup and view all the answers

    Which type of Chalcedony has a characteristic 'botryoidal' crystal growth habit?

    <p>Fire Agate</p> Signup and view all the answers

    What is the typical treatment process for Treated Black Chalcedony?

    <p>Soaking in a sugar solution and then boiling in sulfuric acid</p> Signup and view all the answers

    Which type of Chalcedony has a characteristic pattern of parallel stripes or bands of contrasting colors?

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

    What is the characteristic of Bloodstone's color?

    <p>Red to brownish red fleck scattered over a dark green background</p> Signup and view all the answers

    Which type of Chalcedony is a type of Jasper with red to brownish red fleck scattered over a dark green background?

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

    Study Notes

    Chalcedony (Quartz) Facts

    • Largest consumers of Treated Black Chalcedony and Agate, a favorite among collectors and the first gemstone used for personal adornment.

    Mohs Scale and Composition

    • 7 on the Mohs scale
    • Composed of silicon and oxygen, with common trace elements of iron oxide

    Variety/Species/Group

    • Quartz group, with various varieties:

      Chrysoprase

      • Finest color: light to medium yellowish green, semitransparent to translucent
      • Can have green to bluish green color
      • Trace element: nickel or chromium (when greenish blue)
      • Chemically treated to improve hue

      Chrysocolla-in-chalcedony

      • Translucent to semitranslucent, intense light blue or blue-green

      Carnelian & Sard

      • Semitransparent to translucent, ranging from yellowish orange to brownish orange

      Onyx

      • Parallel stripes/bands of contrasting colors

      Sardonyx

      • Patterned with white or black bands, alternating with reddish brown bands

      Treated Black Chalcedony

      • Chemically treated gray chalcedony, rare in natural black form

      Blue Chalcedony

      • Light grayish blue to bluish gray, light to medium blue tinged with violet

      Jasper

      • Opaque, variegated or displays straight color bands of brownish red, yellows, and blacks

      Bloodstone

      • Type of jasper with red to brownish red flecks on a dark green background

      Agate

      • Eye-visible, banded markings varying in color and transparency

      Iris Agate

      • Semitransparent to translucent, shows iridescent colors

      Chinese Red Agate

      • Intense red, white, or grayish color bands

      Fire Agate

      • Brownish bodycolor with vivid red, green, and gold spectral colors

    Forming Source and Treatments

    • Forms in pegmatite, volcanic, and sedimentary rocks
    • Agate forms inside gas cavities in volcanic rocks, often creating geodes
    • Fire Agate forms in cavities as a botryoidal growth
    • Common treatments include dyeing, heat treatment, and chemical treatment

    Crystal Structure and Phenomena

    • Cryptocrystalline quartz-aggregates of tiny microscopic crystals
    • Can produce "botryoidal" crystal growth habit
    • Iris Agate and Fire Agate exhibit iridescent colors

    Clarity and Cut

    • Chrysoprase may fade when heated or exposed to sunlight
    • Common cuts: cabochon, carved, inlay, or beads
    • Onyx and Sardonyx are often carved or used in cameos
    • Treated Black Chalcedony is cut into cabochons, tablets, or beads
    • Iris Agate is sliced or carved into designs
    • Chinese Red Agate is carved on a small and large scale
    • Fire Agate is cut into unique cabochons due to irregularity of layers

    Trade Names and Countries of Origin

    • Chrysoprase: "golden apple", "Aquaprase"
    • Blue Chalcedony: "moonstone" or "blue moonstone"
    • Jasper: treated jasper is called "blue onyx" or "Swiss lapis"
    • Chinese Red Agate: Southern Red Agate
    • Countries of origin include Australia, Brazil, India, and the US, among others

    Chalcedony Varieties

    • Chrysoprase: often cut as cabochon or carved, known for its yellowish green to bluish green color
    • Carnelian: typically cut into cabochons or beads, and intaglios, with a semitransparent to translucent orange to brownish orange color
    • Onyx and Sardonyx: often carved into cameos, with parallel stripes of contrasting colors
    • Treated Black Chalcedony: cut into cabochons, tablets, or beads, with a chemically treated gray chalcedony
    • Blue Chalcedony: typically cut as cabochons, with a light grayish blue to bluish gray color
    • Iris Agate: often sliced or carved with iridescent colors
    • Chinese Red Agate: carved on a small and large scale, with intense red, white, or grayish color bands
    • Fire Agate: cut into unique cabochons due to the irregularity of the iridescent layers

    Trade Names

    • Chrysoprase: also known as "golden apple" or "Aquaprase" (bluish green from Africa)
    • Blue Chalcedony: sometimes mistaken for "moonstone" or "blue moonstone"
    • Jasper: treated jasper is called "blue onyx" or "Swiss lapis"
    • Chinese Red Agate: also known as southern red agate

    Countries of Origin

    • Chrysoprase: Queensland, Australia (apple green), Brazil (olive green), Tanzania (yellowish green), India, Czech Republic, Slovakia, and the US
    • Carnelian & Sard: Brazil, India, and Uruguay
    • Onyx and Sardonyx: Brazil, Madagascar, the US, and Uruguay
    • Treated Black Chalcedony: Brazil
    • Blue Chalcedony: California’s Mojave Blue, US states of Oregon and Washington, Namibia, and Turkey
    • Bloodstone: Australia, Brazil, China, India, and the US
    • Agate: Mexico, Brazil, and Uruguay, with other sources in India, Madagascar, China, and the US
    • Iris Agate: Mexico and the US states of Texas and Oregon
    • Chinese Red Agate: southern China, including Yunnan and Sichuan provinces and areas along the Yangtze River
    • Fire Agate: Mexican state of San Luis Potosi and northern Jalisco, Mexico

    Important Facts

    • MOHS scale hardness: 7
    • Variety/species/group: Quartz
    • Color/hue range/value: white to milky gray, with various colors depending on the type
    • Crystal structure: cryptocrystalline quartz-aggregates of tiny microscopic crystals
    • Possible phenomena: Iris Agate and Fire Agate display iridescent colors

    Chalcedony (Quartz) Facts

    • Largest consumers of Treated Black Chalcedony and Agate, a favorite among collectors and the first gemstone used for personal adornment.

    Mohs Scale and Composition

    • 7 on the Mohs scale
    • Composed of silicon and oxygen, with common trace elements of iron oxide

    Variety/Species/Group

    • Quartz group, with various varieties:

      Chrysoprase

      • Finest color: light to medium yellowish green, semitransparent to translucent
      • Can have green to bluish green color
      • Trace element: nickel or chromium (when greenish blue)
      • Chemically treated to improve hue

      Chrysocolla-in-chalcedony

      • Translucent to semitranslucent, intense light blue or blue-green

      Carnelian & Sard

      • Semitransparent to translucent, ranging from yellowish orange to brownish orange

      Onyx

      • Parallel stripes/bands of contrasting colors

      Sardonyx

      • Patterned with white or black bands, alternating with reddish brown bands

      Treated Black Chalcedony

      • Chemically treated gray chalcedony, rare in natural black form

      Blue Chalcedony

      • Light grayish blue to bluish gray, light to medium blue tinged with violet

      Jasper

      • Opaque, variegated or displays straight color bands of brownish red, yellows, and blacks

      Bloodstone

      • Type of jasper with red to brownish red flecks on a dark green background

      Agate

      • Eye-visible, banded markings varying in color and transparency

      Iris Agate

      • Semitransparent to translucent, shows iridescent colors

      Chinese Red Agate

      • Intense red, white, or grayish color bands

      Fire Agate

      • Brownish bodycolor with vivid red, green, and gold spectral colors

    Forming Source and Treatments

    • Forms in pegmatite, volcanic, and sedimentary rocks
    • Agate forms inside gas cavities in volcanic rocks, often creating geodes
    • Fire Agate forms in cavities as a botryoidal growth
    • Common treatments include dyeing, heat treatment, and chemical treatment

    Crystal Structure and Phenomena

    • Cryptocrystalline quartz-aggregates of tiny microscopic crystals
    • Can produce "botryoidal" crystal growth habit
    • Iris Agate and Fire Agate exhibit iridescent colors

    Clarity and Cut

    • Chrysoprase may fade when heated or exposed to sunlight
    • Common cuts: cabochon, carved, inlay, or beads
    • Onyx and Sardonyx are often carved or used in cameos
    • Treated Black Chalcedony is cut into cabochons, tablets, or beads
    • Iris Agate is sliced or carved into designs
    • Chinese Red Agate is carved on a small and large scale
    • Fire Agate is cut into unique cabochons due to irregularity of layers

    Trade Names and Countries of Origin

    • Chrysoprase: "golden apple", "Aquaprase"
    • Blue Chalcedony: "moonstone" or "blue moonstone"
    • Jasper: treated jasper is called "blue onyx" or "Swiss lapis"
    • Chinese Red Agate: Southern Red Agate
    • Countries of origin include Australia, Brazil, India, and the US, among others

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Stone Information - Chalcedony (Quartz) PDF

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser