Where Do Diamonds Come From?: Crash Course Geology #8

Overview

Crash Course Geology explores the geological origins of diamonds, revealing they are not formed from coal but from carbon under extreme pressure and heat deep within Earth's mantle, specifically in cratons. The video debunks the myth of diamond rarity, attributing it to De Beers' historical monopoly, and explains that lab-grown diamonds are geologically identical to natural ones, offering a more ethical and affordable alternative.

Key takeaways

Diamonds are formed from carbon under extreme heat and pressure in Earth's mantle, not from compressed coal.
The perceived rarity of diamonds is a myth largely created by the historical monopoly of the De Beers company.
Kimberlite, a volcanic rock, is the primary source rock for diamonds found in the ground, brought to the surface by powerful eruptions.
Diamonds serve as geological time capsules, offering insights into Earth's deep mantle composition and history through mineral inclusions.
Lab-grown diamonds are chemically and physically identical to natural diamonds, offering a more affordable and ethically sound alternative.
Natural diamond mining can cause significant environmental damage and is linked to dangerous labor practices and funding of conflicts (blood diamonds).

Chapters

0:00 Diamond Composition and Formation Myths

Diamonds are made of carbon atoms tightly bound into a nearly indestructible crystal structure, making them the hardest naturally occurring substance.
Contrary to popular myth, diamonds are not formed from coal under pressure; they originate from carbon in Earth's upper mantle.
Diamonds form in stable, hot, and pressurized cratons, the deep roots of continents, and can originate from depths of over 600 km.

2:21 The Discovery of Kimberlite and Diamond Eruptions

Historically, diamonds were found in alluvial deposits, but in 1870, miners in Kimberly, South Africa, discovered them within kimberlite, a volcanic rock.
Kimberlite eruptions, triggered by continental breakup, blast molten rock and chunks of deep Earth rock to the surface, bringing diamonds with them.
Most kimberlite eruptions occurred 250-50 million years ago, and diamonds themselves began forming up to 3 billion years ago.

7:19 The Myth of Rarity and Lab-Grown Diamonds

The perception of diamond rarity was largely perpetuated by Cecil Rhodes and the De Beers Mining Company, which controlled nearly all diamond mines globally for decades.
Lab-grown diamonds, first created by General Electric in the 1940s, are geologically identical to natural diamonds, formed under intense heat and pressure.
Lab-grown diamonds are significantly cheaper (up to 85% less) and considered a more ethical choice due to the environmental and labor issues associated with natural diamond mining, including blood diamonds.

Summary, takeaways, and chapters were generated by AI from the video's transcript and may contain errors. The video belongs to its creator, CrashCourse.