GIA Diamond Formation, Mining, and the Diamond Market 3 — Questions and Answers
Question 1: Lamproite pipes are volcanic structures that, like kimberlites, can host diamonds. Which famous deposit is associated with lamproite?
- Argyle mine in Australia (Correct answer)
- Orapa mine in Botswana
- Mir mine in Russia
- Premier mine in South Africa
Correct answer: Argyle mine in Australia
The Argyle mine in Western Australia is the world's most productive diamond mine by volume and is hosted in a lamproite pipe.
Question 2: During the diamond sorting process, rough diamonds are primarily separated by:
- Size, shape, quality, and color (Correct answer)
- Carat weight and country of origin
- Fluorescence and refractive index
- Crystal habit and cleavage direction only
Correct answer: Size, shape, quality, and color
Rough diamond sorting classifies stones into thousands of categories based on size, shape, quality, and color to determine their best use.
Question 3: What is the Kimberley Process Certification Scheme (KPCS) designed to prevent?
- Trade in conflict diamonds used to finance rebel movements (Correct answer)
- Synthetic diamonds entering the natural diamond supply
- Undisclosed treatments on polished diamonds
- Tax evasion in the rough diamond trade
Correct answer: Trade in conflict diamonds used to finance rebel movements
The KPCS is an international governmental certification scheme launched in 2003 to stop the flow of conflict (blood) diamonds.
Question 4: Which term describes diamonds found embedded in the host rock of a kimberlite pipe before excavation?
- Primary deposit (Correct answer)
- Secondary deposit
- Alluvial deposit
- Marine deposit
Correct answer: Primary deposit
Primary deposits are diamonds found in their original igneous host rock, such as kimberlite or lamproite, before erosion.
Question 5: Sub-level caving is a form of underground mining used when:
- The kimberlite orebody extends too deep for open-pit operations (Correct answer)
- Alluvial gravels are found in shallow riverbeds
- Marine deposits are recovered from the seafloor
- Surface weathering has already loosened the ore
Correct answer: The kimberlite orebody extends too deep for open-pit operations
Sub-level caving is used in deep underground kimberlite mines where open-pit methods are no longer economically viable.
Question 6: Botswana's Orapa mine is significant because it is:
- One of the largest kimberlite pipes by area ever discovered (Correct answer)
- The world's oldest continuously operating alluvial mine
- The deepest underground diamond mine in the world
- The primary source of Type IIb blue diamonds
Correct answer: One of the largest kimberlite pipes by area ever discovered
Orapa, discovered in 1967, is one of the largest kimberlite pipes in the world by surface area and is a major producer for Debswana.
Question 7: What economic factor most directly determines a rough diamond's value before cutting?
- Its potential yield and quality of polished stones it can produce (Correct answer)
- The country from which it was mined
- Its fluorescence under UV light
- The mining company that extracted it
Correct answer: Its potential yield and quality of polished stones it can produce
Rough diamond value is based on the size, quality, and color of the polished diamonds that can be fashioned from it, known as its potential yield.
GIA Diamond Formation, Mining, and the Diamond Market 3
Lamproite pipes are volcanic structures that, like kimberlites, can host diamonds.
Which famous deposit is associated with lamproite?