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Questions and Answers
What is the typical color of the Schorl species of tourmaline?
What is the typical color of the Schorl species of tourmaline?
Which element is rarely concentrated in elbaite, a species of tourmaline?
Which element is rarely concentrated in elbaite, a species of tourmaline?
What is a characteristic of Liddicoatite, a species of tourmaline?
What is a characteristic of Liddicoatite, a species of tourmaline?
What type of stone is often carved and exported to China?
What type of stone is often carved and exported to China?
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What is the typical formation of Dravite, a species of tourmaline?
What is the typical formation of Dravite, a species of tourmaline?
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What is a characteristic of most gem tourmalines?
What is a characteristic of most gem tourmalines?
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What elements do silicates of tourmaline share?
What elements do silicates of tourmaline share?
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What is responsible for the blue color of Paraiba Tourmaline?
What is responsible for the blue color of Paraiba Tourmaline?
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How are long, dark rough tourmalines often cut to lighten their color?
How are long, dark rough tourmalines often cut to lighten their color?
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What is a characteristic of green and blue tourmalines when cut with the table parallel to the crystal's length?
What is a characteristic of green and blue tourmalines when cut with the table parallel to the crystal's length?
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Why are Chrome tourmalines often flattened?
Why are Chrome tourmalines often flattened?
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What is a common phenomenon observed in most green tourmalines?
What is a common phenomenon observed in most green tourmalines?
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What is the characteristic of inclusions in Red and Pink Tourmaline?
What is the characteristic of inclusions in Red and Pink Tourmaline?
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What is the typical size range of Red & Pink Tourmaline gems?
What is the typical size range of Red & Pink Tourmaline gems?
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What is the name of the cut created specifically for Zircon to show off its luster and fire?
What is the name of the cut created specifically for Zircon to show off its luster and fire?
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What is the characteristic of Cat's Eye Tourmaline inclusions?
What is the characteristic of Cat's Eye Tourmaline inclusions?
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What is the term for the long, hollow tubes with crystals or gas bubbles found in Tourmaline?
What is the term for the long, hollow tubes with crystals or gas bubbles found in Tourmaline?
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What is a common phenomenon observed in Tourmaline?
What is a common phenomenon observed in Tourmaline?
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What is done to Cat's Eye Tourmaline to remove unsightly inclusions or dark staining?
What is done to Cat's Eye Tourmaline to remove unsightly inclusions or dark staining?
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What is the term for the blue color of Tourmaline?
What is the term for the blue color of Tourmaline?
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What is the name for the heat-treated Zircon that produces a colorless gemstone?
What is the name for the heat-treated Zircon that produces a colorless gemstone?
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Where are Red and Pink Tourmaline primarily cut?
Where are Red and Pink Tourmaline primarily cut?
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What is the name for the dark chromite crystals or reflective inclusions found in Peridot?
What is the name for the dark chromite crystals or reflective inclusions found in Peridot?
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What is the primary cutting center for Blue and Green Tourmaline?
What is the primary cutting center for Blue and Green Tourmaline?
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What is the characteristic of 'Savannah' tourmalines?
What is the characteristic of 'Savannah' tourmalines?
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What is the typical color range of Paraíba Tourmaline?
What is the typical color range of Paraíba Tourmaline?
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What is the characteristic of Chrome Tourmaline?
What is the characteristic of Chrome Tourmaline?
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What is the characteristic of Green Tourmaline?
What is the characteristic of Green Tourmaline?
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What is the characteristic of Pink Tourmaline?
What is the characteristic of Pink Tourmaline?
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What is the characteristic of Cat's Eye Tourmaline?
What is the characteristic of Cat's Eye Tourmaline?
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To lighten a dark rough tourmaline they orient the table in what way ?
To lighten a dark rough tourmaline they orient the table in what way ?
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Study Notes
Gemstones
- Tourmaline:
- Available in sizes up to 20 cts, with calibrated sizes including 6x4mm, 7x5mm, and 8x6mm ovals and octagons, and rounds of 2.5 to 5 mm
- Countries of origin include Brazil, Africa, Afghanistan, Pakistan, Russia, and the US
- Paraiba tourmaline is found in northern Brazil and Africa, with the largest deposit being the Jonas Mine in Brazil
- Green and blue tourmaline are found in Brazil, Afghanistan, the US, and Africa, with fine chrome tourmaline coming from Myanmar
- Red and pink tourmaline are found in Brazil, Nigeria, Afghanistan, and the US
- Peridot:
- Found in the US, China, Vietnam, Finland, Pakistan, and Myanmar
- Finest large peridots come from Myanmar and the Himalayas of Pakistan
- Commercial material is found in China, the US, Vietnam, Mexico, Australia, Ethiopia, Norway, Sri Lanka, and New Mexico
- Zircon:
- Found in Southeast Asia, Madagascar, Sri Lanka, Myanmar, Vietnam, Cambodia, and Australia
- Hard to cut due to brittleness, often cut into brilliant cuts
- Colors range from colorless to yellow, green, red, reddish-brown, and blue hues
Characteristics
- Tourmaline:
- Trichites, long hollow tubes with crystals, gas bubbles or water are common
- Red and pink tourmaline often have inclusions, which can affect the price
- Peridot:
- Strongly doubly refractive
- Eye-clean, with inclusions of minute octahedral crystals of chromite
- Graded as either "grade A" (eye-clean with a pure, yellowish-green hue), "grade B" (clean but pale in color), or included but of reasonably good color
- Zircon:
- Refractive index, double refraction, and specific gravity
- Often heat-treated to produce a range of colors, including blue, green, and red
Formation and Composition
- Tourmaline:
- Formed in pegmatites
- Silicates that share the elements aluminum, boron, and fluorine
- Trace elements of iron, titanium, and manganese induce different colors
- Peridot:
- Formed in volcanic rocks called basalts
- Silicate of iron and magnesium
- Trace elements of iron create its hue
- Zircon:
- Formed in igneous and metamorphic rocks
- Composition varies depending on the type of rock it forms in
Cutting and Trading
- Tourmaline:
- Cut into long rectangles due to crystal structure
- Table orientation affects the color and clarity of the gem
- Paraiba tourmaline is often custom-cut into brilliant cuts, commonly pear and oval shapes
- Peridot:
- Cut in Thailand, Germany's Idar-Oberstein, and China
- Burmese peridot is cut in Thailand, while Arizona peridot is cut in Germany and Thailand
- Zircon:
- Cut in Thailand
- Popular due to its durability and affordability on the home shopping network
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Description
Test your knowledge of the colors and chemical compositions of zircon and tourmaline gemstones. Learn about the different hues of these stones and how they are influenced by heat treatment and the presence of various elements. Explore the world of gemstones and their unique properties!
