Podcast
Questions and Answers
What is the purpose of 'oiling' in emerald treatment?
What is the purpose of 'oiling' in emerald treatment?
- To enhance the color of the emerald
- To create a synthetic emerald
- To fill in fractures and improve clarity (correct)
- To change the cut of the emerald
What is the term used to describe the finest emerald color?
What is the term used to describe the finest emerald color?
- Zambian
- Jardin
- Colombian (correct)
- Hydrothermal
What is the typical Mohs scale hardness of emeralds?
What is the typical Mohs scale hardness of emeralds?
- 9 to 10
- 7.5 to 8 (correct)
- 8.5 to 9
- 6.5 to 7
What is the primary synthetic process used to create emeralds?
What is the primary synthetic process used to create emeralds?
Which of the following emerald cuts allows for a minimum of eight loss?
Which of the following emerald cuts allows for a minimum of eight loss?
What is the main factor that affects the color of emeralds?
What is the main factor that affects the color of emeralds?
What is the term used to describe inclusions in emeralds?
What is the term used to describe inclusions in emeralds?
In which type of rock environments can emeralds be formed?
In which type of rock environments can emeralds be formed?
What is the characteristic of a trapiche emerald?
What is the characteristic of a trapiche emerald?
Which of the following mines is the largest and most productive emerald mine in Zambia?
Which of the following mines is the largest and most productive emerald mine in Zambia?
What is the shape of the crystal structure of emeralds?
What is the shape of the crystal structure of emeralds?
What is the term for the phenomenon where the cut gem's face-up color appears bluish green when the cutter orients the table perpendicular to the crystal's length?
What is the term for the phenomenon where the cut gem's face-up color appears bluish green when the cutter orients the table perpendicular to the crystal's length?
Study Notes
Emerald Characteristics
- GIA's clarity enhancement report levels: F1 (minor), F2 (moderate), and F3 (significant)
- Common treatments: oiling, fracture filling, and dyeing
- Common cuts: Emerald, round, oval, pear, marquise, and heart shapes, with brilliant, step, or mixed-cut facet arrangements
- Calibrated sizes: 5x3 mm to 7x5 mm range, with rounds available in sizes below 4 mm
Trade Names and Origin
- "Colombian" emeralds: finest emerald color
- "Zambian" emeralds: slightly darker and more bluish than Colombian emeralds, often with higher clarity
- "Jardin" inclusions: describe inclusions in emeralds
- Countries of origin: Colombia, Zambia, Brazil, Afghanistan, Pakistan, Russia, Zimbabwe, Madagascar, and China
Synthetic Emeralds
- Main synthetic processes: flux and hydrothermal, with hydrothermal being the primary method
- Jacques Joseph Ebelman: first to use the flux process to synthesize emerald crystals
- Johann Lechleitner: synthesized emerald hydrothermally in 1960
Market and Properties
- Largest consumers: US, Europe, Colombia, Brazil
- Mohs scale: 7.5 to 8
- Variety/species/group: Beryl
- Color/hue range/value: most prized emeralds are highly transparent, bluish green to green, with strong to vivid saturation and medium to medium-dark tone
Composition and Structure
- Chemical composition: trace elements include chromium, vanadium, iron, beryllium, aluminum, silicon, oxygen
- Forming source: metamorphic-rock environments, where pegmatites intersect with schists, or sedimentary rock
- Crystal structure: elongated six-sided prism
Phenomena and Characteristics
- Possible phenomena: dichroism
- Clarity characteristics: color zoning, fractures, liquid and multiphase inclusions, mineral crystals, needles, and growth tubes
- Trapiche emerald: dark inclusions forming a pattern like the spokes of a wheel
- "Oil-drop effect": occurs in the finest Colombian emeralds, with a roiled pattern similar to honey or oil
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Description
Get to know the characteristics of emeralds, including their largest consumers, Mohs scale, variety, color range, and chemical composition. Test your knowledge of this precious gemstone!
