EOSC 118 Final Test Questions with 100% Correct Answers
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EOSC 118
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EOSC 118
EOSC 118 Final Test Questions with 100% Correct Answers
What is similar about the geological setting in which diamonds and xenocrystic corundum are formed? - Answer- Both are formed at great depths in the Earth, and brought to the surface by magma of a different composition
In four pegmati...
EOSC 118 Final Test Questions
with 100% Correct Answers
What is similar about the geological setting in which diamonds and xenocrystic
corundum are formed? - Answer- Both are formed at great depths in the Earth, and
brought to the surface by magma of a different composition
In four pegmatite classes, which one is most likely to contain gemstones? - Answer-
Rare-element
Where are the famous districts of gem bearing pegmatites? - Answer- Us
Italy
Pakistan
What condition is critical for pegmatite formation? - Answer- High volatile concentration
Volatiles allow diffusion of elements within the pegmatite melt and hydrothermal fluids
What happen if volatile concentration is too high? - Answer- Corrosion of minerals
How can we determine whether diamond have impurity or not? - Answer- Chemically
analyze
What cause the colour of green diamonds? - Answer- Natural irradiation
What happen to the diamond if the temperature is too high or the depth is not deep
enough? - Answer- Turns into graphite
What is VVS1? - Answer- Inclusion cannot be visible to unaided human eye
Difference in colour E and F for diamond? - Answer- Colour difference of the diamond
will be so slight that untrained eye will not notice the difference
Difference in colour D and G for diamond? - Answer- Minimal price difference for small
stone
Grows dramatically with carat weight
What will be the cause of colour difference, if only the light source has changed? -
Answer- Colour change effect
, What will be the cause of colour difference, if only the stone changed orientation? -
Answer- Pleochroism or trichroism
Which property of oil make them to be the most appropriate treatment for beryl? -
Answer- Their refractive index is similar to beryl
Why is emerald rare? - Answer- Be is rare in Earth's crust
Cr and V are rare in Earth's crust
Be, Cr, V are typically found in different types of rock
Lower specific gravity make them hard to concentrate
What are the important identifiers for tourmaline in hand sample? - Answer- **has very
poor cleavage, but really hard to observe in hand sample
Hardness
Pseudo-hexagonal habit
Vertical striations along the c-axis of the crystal
Dichroism
What type of metal deposit is turquoise typically associated with? - Answer- Copper
(copper porphyry deposits)
**unique element in turquoise is copper, hence, requires copper to form
What will be the easiest way to distinguish a faceted alexandrite? - Answer- View the
gemstone under both normal daylight and incandescent light to see if it changes colour
(red >>> blue)
What was the first ancient civilization known to have used gold? - Answer- Egypt
Most orogenic gold deposits were formed during which time periods? - Answer- 600 to
50 Ma
2100 to 1800 Ma
2800 to 2550 Ma
How old are rocks in the Canadian Shield? - Answer- ~4 billlion
What are the reasons that platinum is popular in jewellery? - Answer- Durable
Relatively high hardness
What is the most important deposits for PGE? Why? - Answer- Bushveld Complex
-the complex accounts for 80% of global PGE production
Is silver most commonly mined as the primary resource of a mine? - Answer- No
It often come from mines that are primarily looking for other resources
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