Exploring for Diamonds (Chapter 5, Key Terms & Key Concepts) Flashcards
A deposit where gems are
eroded from their source rock, then transported away from the source and further
concentrate
Aluvial deposit
Large-scale character
sampling.
Bulk sampling
Testing for the size,
shape, clarity, and color of the diamonds in
a deposit.
Character sampling
Diamond rough with good
enough size, shape, clarity, and color to
produce a polished stone suitable for use
in jewelry.
Cuttable rough
Separating heavier
materials (diamonds) from a test sample.
Gravity sorting
Minerals formed
together with diamonds at great depths
and brought to the surface by the same
kimberlites or lamproites.
Indicator minerals
Diamond rough suitable
for use in tools, drills, abrasives, and other
industrial applications.
Industrial rough
Secondary diamond
deposit carried by rivers or streams to the
ocean floor or shoreline.
Marine deposit
Screening for the
presence of tiny diamonds in a sample.
Microdiamond testing
Concentration of diamond in a
potentially mineable deposit.
Ore grade
Gems found in the rock
that carried them to the surface.
Primary deposit
Gems found away
from their primary source.
Secondary deposit
Growing diamond demand helps motivate the
search for new diamond sources.
Key Concept
It takes many years and millions of dollars to
develop a diamond mine.
Key Concept
Modern diamond exploration involves careful
planning and sophisticated equipment.
Key Concept
For a mine to be successful, the projected value
of its diamonds must be more than the cost of
mining them.
Key Concept
Diamond exploration specialists start by looking
for the oldest parts of the earth’s crust.
Key Concept
Most diamonds mined today come from pipes.
Key Concept
A mining company must consider a potential
mine’s location, climate, and political conditions
along with its content.
Key Concept
Only a small percentage of known diamond deposits are mined because most
are not profitable.
Diamonds classified as cuttable can be 100 times more valuable than
industrial diamonds.
Most of the diamonds mined today come from
pipes.
Indicator minerals in kimberlite and lamproite include tiny
diamonds
Gravity sorting separates diamonds from
lighter materials.
A mine’s potential profitability depends in part on
its ore grade.
For more than 2,000 years, the only known diamond sources were
alluvial.
The first step in exploring for diamonds is to
look for the oldest parts of the earth’s crust.
The concentration of diamonds within a pipe is called
ore grade.
A profitable mine
produces diamonds whose value is higher than the mine’s operating costs.
Diamond rough suitable for use in tools, drills, and abrasives is
industrial quality.
Diamond rough suitable for use in jewelry is called
cuttable.
Diamond deposits found at the ocean’s shore are
marine deposits.
Diamonds are more concentrated in
marine deposits.
To focus their search for diamond deposits, geologists look for
indicator minerals.
