Diamond (Rough)

Hardness: 10 (Mohs scale), Color: Typically colorless or white, but can occur in shades of yellow, brown, green, blue, pink, red, orange, and black due to impurities or structural defects. Luster: Adamantine (brilliant, like a polished diamond). Crystal Structure: Isometric (cubic), commonly forming octahedrons, dodecahedrons, and cubes. Cleavage: Perfect octahedral cleavage (though rarely observed due to its hardness). Specific Gravity: 3.5–3.53.

Formation Process: Diamonds form under extremely high pressure and high temperature conditions deep within the Earth's mantle, about 150 to 200 kilometers (90 to 120 miles) below the surface. They are brought to the surface through deep-seated volcanic eruptions, typically in kimberlite and lamproite pipes. Geological Age: Most natural diamonds are between 1 billion and 3.5 billion years old, predating the existence of life on much of Earth. Environment: Found in the mantle and transported to the surface in specific volcanic rock formations.

Industry: Over 70% of diamonds are used for industrial purposes, such as cutting, drilling, grinding, and polishing tools, due to their extreme hardness. Construction: Used in diamond-tipped saw blades and drill bits for cutting concrete, asphalt, and stone. Jewelry: Highly prized as gemstones in rings, necklaces, earrings, and other luxury items due to their brilliance and durability. Collecting Value: Rough diamonds are collected by mineral enthusiasts, and polished diamonds hold significant monetary value.

Diamonds are the hardest known natural material. The word 'diamond' comes from the ancient Greek word 'adámas', meaning 'unbreakable' or 'invincible'. Famous diamonds include the Hope Diamond (blue), the Cullinan Diamond (the largest gem-quality rough diamond ever found), and the Koh-i-Noor. They are the birthstone for April.

How to Identify in the Field: Rough diamonds typically occur in octahedral, dodecahedral, or cubic crystal forms, often with rounded edges or characteristic trigons (triangular growth marks) on their faces. Their adamantine luster (even when rough) and extreme hardness are key identifiers. When found in alluvial deposits, they will be unusually hard and often have a greasy feel. Common Locations: Major diamond deposits are found in Russia, Botswana, Canada, Australia, South Africa, Angola, and the Democratic Republic of Congo. Tips for Collectors: Diamonds found in their natural state often have a dull or 'greasy' appearance on their outer surface compared to their brilliant interior once cut. Their extreme hardness means they will scratch almost any other mineral. Field identification usually requires associated geological indicators, such as the presence of kimberlite or lamproite rocks, or specific indicator minerals found with diamonds (e.g., pyrope garnet, chromite, ilmenite, olivine, diopside).