Download Organisation Deutsche Internationale Schule Diamonds

Diamonds can be natural or synthetic;
Mechanical Properties
Optical Properties
Natural diamonds;
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• Lustrous (shiny)
• Pure diamond is the most transparent material
known
• High dispersion and high refractive index
• Natural diamond is formed when carbon crystallizes
• Pressure must be between 45 and 60 kilo bars and the
temperature between 900 and 1300 °C.
• These conditions occur naturally only in the
lithospheric mantle, below the continental plates, and
at meteorite crash sites
• Natural diamond sources have been discovered in
approximately 35 different countries
• The most notable diamond deposits are in Africa
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Hard-hardest natural material on earth. (10 Mohs)
The least compressible and stiffest substance
Brittle-splits along its crystal cleavage planes when
receiving a certain impact
Dense-despite low atomic weight of carbon
Synthetic;
• Produced by the process of HPHT (High
Pressure Temperature Synthesis)
• Graphite and a metallic catalyst are placed
in a hydraulic press under high temp. and
pressures for a couple of hours
• Graphite is converted to diamonds
• usually to small and too flawed to use as
gemstones
• But useful on drill bits and cutting tools
Did you know?
Chemical Properties
Structure and bonding
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Giant molecular structure.
Each carbon atom is covalently bonded to four other carbon atoms
Covalent bonds are strong
Contains many covalent bonds therefore a lot of energy is required to
separate the atoms in a diamond (high ionization energy)
• High melting point and boiling point
• Is an allotrope of carbon
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Insoluble in water
High melting and boiling point
Negative electron affinity
Good chemical stability does not react with acid and
alkali under room temperature, so acid and alkali
can be used to refine synthetic diamonds
Allotropes of carbon include diamond, graphite and
soot.
all are forms of the element carbon - each have
chemical symbol C
Allotropes of carbon differ greatly in their structure
and properties
• Diamonds are the hardest, natural
substance on earth
• Diamonds are brought closer to the
earth’s surface through volcanic
activity
• The earliest written proof of the
existence of diamonds dates back
to around 500BC
• The rarest colours of diamonds are
red and blue
• The Kimberley mines have
produced some of the most
famous diamonds, some that even
the Queen of England wears.
School: Deutsche
Internationale Schule
Johannesburg
Teacher: Mrs Machlachlan
Learners: Neil Hiestermann,
Rebecca Organ, Sebastian
Welke