Week 7 - Gemmology Flashcards
What is gemmology?
The study of gemstones, including their origins, identification, treatment, and commercial use.
What are key aspects assessed in gemmology?
Natural vs. synthetic, treatments, genuine vs. simulant, and age.
What materials can gemstones be made from?
Minerals, rocks, glass, or synthetic materials.
Give examples of organic gemstones.
Amber, pearls, ivory, coral, jet.
What are the key attributes of a gemstone?
Beauty, durability, rarity, desirability, and value.
What are the two types of gemstone mining?
Artisanal (informal) and commercial mining.
What are the cleavage categories of gemstones?
Perfect, good, poor, and none.
Name a gemstone with perfect cleavage.
Diamond.
What is an allochromatic gemstone?
A gemstone where colour comes from trace elements.
Name a gemstone coloured by chromium.
Ruby (red), emerald (green).
What is an idiochromatic gemstone?
A gemstone where colour is due to an essential element in its chemistry.
Name a gemstone coloured by copper.
Turquoise (blue-green).
What is chatoyancy?
The cat’s-eye effect caused by parallel inclusions.
What causes asterism?
Star-like light reflections in rubies and sapphires.
What is fire in gemstones?
Light dispersion into rainbow colours, seen in diamonds.
What are the three transparency levels in gemstones?
Transparent, translucent, opaque.
What are the three types of inclusions?
Single-phase, two-phase, three-phase.
What is colour zoning?
Variation in colour due to growth conditions.
Name three varieties of beryl.
Emerald, aquamarine, morganite.
What gives emeralds their green colour?
Chromium and vanadium.
What treatment is common for emeralds?
Oil or resin filling for fracture repair.
What are the two main varieties of corundum?
Ruby (red) and sapphire (blue).
What makes corundum so durable?
It has a Mohs hardness of 9, second only to diamond.
Where is most corundum found?
In placer gravels.
What does a polariscope determine?
If a gemstone is isotropic or anisotropic.
What does a refractometer measure?
The refractive index (RI) of a gemstone.
What does a spectroscope do?
Identifies elements in a gemstone by analysing light absorption patterns.
