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level: Toughness

Questions and Answers List

Question	Answer
Toughness is a property of what part of the gem material?	Body
What term refers to a break that can occur in both non-crystalline and crystalline materials?	Fracture
What terms refers to a break that can only occur along a particular direction of the structure in a crystalline material?	Cleavage
What is the name of this type of fracture with concentric ripples often seen on the corners of certain gemstones?	Conchoidal
What type of fracture is rough, jagged and uneven?	Hackly
What type of fracture is visible as an even, shiny or curved appearance?	Smooth
What is the appearance of a cleavage fracture?	Flat
In what type of materials can cleavage not occur?	Amorphous
Perfect, good, fair or poor are terms used to describe what in terms of cleavage?	Quality
How many directions of cleavage are found in a diamond?	Four
What type of cleavage quality does a diamond have?	Perfect
How many directions of cleavage are found in Calcite?	Three
How many directions of cleavage are found in tourmaline?	One
What is the cleavage quality of tourmaline?	Poor
What is the term used to descibe cracks along cleavage faces within a gemstone?	Incipient cleavage
What is the term used to describe a cleavage break in a gemstone that is difficult to determine between fracture or cleavage?	Indistinct Cleavage