How to identify Yellow Diamond

To correctly identify Yellow Diamond (Diamond (Carbon)), check each of these features in order. Many rocks and minerals look alike, so cross-reference multiple properties before deciding.

Step-by-step identification

1. 1

   Color

   Overall color and any zoning or banding

   Ranges from faint yellow to intense, vivid canary yellow. The color should be evenly distributed.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Adamantine (diamond-like), exceptionally brilliant.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Smooth to slightly rough on natural crystal faces; faceted surfaces are perfectly smooth.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Typically octahedral, dodecahedral, or cubic crystals in their natural state. Often found as fragments or polished facets in jewelry.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Perfect octahedral cleavage in four directions {111}. This means it can be split along these planes, though it is extremely difficult due to its hardness.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Primary deposits are found in kimberlite and lamproite pipes, which are ancient volcanic conduits. Secondary (alluvial) deposits are found in riverbeds and coastal plains where diamonds have been eroded from their primary sources and transported.

Key Facts

Hardness

10 (Mohs scale), the hardest known natural mineral

Specific Gravity

3.50-3.53 g/cm3

Crystal System

Cubic (isometric)

Color

Colorless, yellow, brown, green, blue, pink, red, black (yellow is due to nitrogen impurities)

Luster

Adamantine

Transparency

Transparent to opaque

Fracture

Conchoidal to uneven

Cleavage

Perfect octahedral {111}

Composition

Pure carbon (C)

Physical characteristics

• Crystal Habit: Octahedral, dodecahedral, cubic, or combinations thereof; also massive, granular, or bort (poorly crystallized aggregates).
• Cleavage Type: Perfect in four directions, forming an octahedron.
• Fracture Type: Conchoidal to uneven, brittle.
• Tenacity: Brittle, despite extreme hardness.
• Luster Type: Adamantine (brilliant, like a polished diamond); unpolished crystals may appear greasy.

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