EOSC 118 Chapter all chapters: EOSC 118 notes
14 Jun 2018
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EOSC 118
The largest Cullinan Diamond is the largest faceted diamond in the world.
The largest cut diamond weighs 545 carats and is called Golden Jubilee
Significant people and groups
Gold
- South Africa 11% of worlds newly mined gold (recent china 12%)
- Barrick Gold of Canada: largest non-Chinese producer of gold; 10%; 27 in 4;
AngloGold Ashanti of South Africa: 7%; 20 in 10
- Used for jewellery (83%), electronics, currencies and investments.
Platinum Group Metals (PGMs)
- Platimum(Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), iridium (Ir) and osmium (Os)
naturally together.
- Higher melting point than gold.
- Price largely determined by supply ( production in South Africa)
- South Africa (79%)
Russia (12%)
US (2%)
Canada (4%)
- Used for high-tech applications
Diamonds
- De Beers Consolidated Mines Ltd. has essentially controlled the entire diamond market since its
inception in 1888
- Steps:
1. Geological prospecting, exploration and development of mine site
2. Production of rough diamonds from mine(s) go to the Central Selling Organization
3. Sorting, valuing, and sighting of rough stones (size, colour, and clarity) by DTC to
sightholders
4. Cutting and polishing into finished diamonds
5. Jewellery and gem manufacturing and distribution
6. Retail stores and sales
- 20% polished goods
--20% gemstone 80% industrial applications (abrasives)
Retailer and Industry Organizations
Various laboratories conduct evaluations:
- Gemological Institute of America (GIA)
- International Gemological Institute (IGI)
- American Gem Society (AGS)
- European Gemological Laboratories (EGL)
Auction Houses and Luxury Brands
- Auction houses: Christie's and Sotheby's
- Brands: Tiffany & Co. , Harry Winston, Inc. and Van Cleef and Arpels
Current Trends in the Media
- Modern exploration and mining practices coupled with increased diversification of global wealth
has generated a significant market accessible to individuals other than royalty and the ultra-wealthy.
- The increase in demand has increased production, and therefore brought prices down considerably
based on economies of scale.
Arts and Design Competitions
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Audition-sponsored by the World Gold Council and AngloGold Ashanti
- For high-karat gold
What consumers care about?
• Where their jewellery came from
• What impact it has had
• Land of its origin
Kimberley Process: Industry-driven set of regulations, was voluntarily adopted by the majority of
the diamond producing and consuming countries of the world in a fight to quench the trade of illicit
diamonds.
Key Geoscience Concepts
Diamonds come from upper mantle
Process of scientific investigation
1. Compile observations
2. Form a Hypothesis
3. Test the Hypothesis
4. Repeated testing
5. If a Theory or group of theories are always observed to happen it could be raised to the level of a
Law.
6. Continual re-examination.
Earth’s Interior
Lithosphere 岩石圈
Asthenosphere 岩流圈
Mantle 地幔
Outer core
Inner core
Three main types of plate boundaries are convergent, divergent, and transform.
• Divergent: plates move away from each other. E.g. Mid-Atlantic Ridge (MAR)
• Convergent (Destructive) Plate Boundaries: two plates move toward each other and collide
• Transform Plate Boundaries
Gems: valuable minerals that originated from an original source rock
Gemstone is any mineral that is highly valued for its beauty, durability, and rarity.
Rock (i) naturally occurring aggregates of (ii) minerals.
Igneous Rocks 岩浆岩 crystallize (a process sometimes called solidification) from a molten material
(called a melt or magma) to form a rock composed of interlocking crystals.
Metamorphic Rocks 变质岩are formed by the alteration of pre-existing rocks (igneous,
metamorphic, and sedimentary) via metamorphism.
Sedimentary Rocks 沉积岩 are transformed into rock via a process called diagenesis or lithification
which physically cements the sedimentary grains together.
Rock Cycle
Partial melting of mantle material forms magma; magma crystallizes to form igneous rocks;
weathering and erosion of igneous and metamorphic rock produces sediments which lithify to form
sedimentary rocks; some igneous and sedimentary rock undergo tectonic burial and metamorphism
to form metamorphic rock.
L6 Elements, Matter and Precious Metals
Atom (原子) made up of protons, neutrons 中子, electrons.
valence state 化学价
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ions 离子 cations 离子
ionic radius which is measured in units called Angstroms
Atomic Mass total number of neutrons and protons
Elements
- ~ 117 known elements; ~90 of elements occur naturally
Compounds
Two or more elements join together they form a compound
Mixtures
Comprised of two or more compounds that are not interacting through chemical bonding
Ionic bonding
一个失离子 一个得离子 例：NaCI
Covalent bonding
共价结合
Metallic bonding
Valence electrons in metallically bonded compounds are shared throughout the entire material (not
simply between two atoms) and are free to move about.
States of Matter
- Solid, liquid, and gas.
The Periodic Table of the Elements
- 7 periods (or rows) of elements, 18 groups (or columns), and a subset of two periods called the
Actinides and Lanthanides.
- Alkali metals 碱
- Alkaline earth metals
- Transition metals
- Semi-metals
- Metalloids
- Nonmetals
- Halogen
- Noble gases
- ...Plus the lanthanides and actinides...
Ppm:
- Parts per million. Referred when elements are very rare.
Native Elements
- When elements occur by themselves in rock (i.e., not chemically bonded to other elements), they
are considered to be in their native state
- There are 20 elements and all are either metals, semi-metals, or non-metals.
- Native metals make-up the largest group
Traits of native metal minerals
- Electrical conductivity, good thermal conductivity, high densities, malleability, ductility, and a
metallic luster.
Purity
Karats – for gold, silver, platinum, and etc.
*Carat- measurement of the weight of gemstone.
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Document Summary
The largest cullinan diamond is the largest faceted diamond in the world. The largest cut diamond weighs 545 carats and is called golden jubilee. South africa 11% of world(cid:495)s newly mined gold (recent china 12%) Barrick gold of canada: largest non-chinese producer of gold; 10%; 27 in 4; Anglogold ashanti of south africa: 7%; 20 in 10. Used for jewellery (83%), electronics, currencies and investments. Platimum(pt), palladium (pd), rhodium (rh), ruthenium (ru), iridium (ir) and osmium (os) naturally together. Price largely determined by supply ( production in south africa) De beers consolidated mines ltd. has essentially controlled the entire diamond market since its inception in 1888. Brands: tiffany & co. , harry winston, inc. and van cleef and arpels. Modern exploration and mining practices coupled with increased diversification of global wealth has generated a significant market accessible to individuals other than royalty and the ultra-wealthy.
