Diamond in kimberlite An uncut diamond embedded in kimberlite, a type of igneous rock in which many diamonds are found. (more) How Are Diamonds Made? Ask the Chatbot a Question More Actions Share Share Share to social media Facebook X URL https://www.britannica.com/topic/How-Are-Diamonds-Made Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article.

　　External Websites Ask the Chatbot a Question Written and fact-checked by The Editors of Encyclopaedia Britannica Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors. The Editors of Encyclopaedia Britannica Last Updated: Mar 18, 2025 • Article History Table of Contents Table of Contents Ask the Chatbot In nature, diamonds are created deep within Earth’s mantle under extreme conditions. They form at depths exceeding 120 kilometers (75 miles) where temperatures soar and pressures are immense. Over billions of years, carbon atoms bond in a crystal structure that results in the hardest known natural substance. These diamonds are then brought closer to Earth’s surface through volcanic eruptions, where they can be mined from kimberlite pipes, alluvial gravels, or glacial tills. Synthetic diamonds, on the other hand, replicate the natural formation process in a controlled environment. The two processes for making synthetic diamonds start with a small diamond as ...(100 of 187 words)

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