How to identify Yellow Gemstone

To correctly identify Yellow Gemstone (Unidentifiable (likely Citrine, Yellow Sapphire, or Cubic Zirconia)), 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 pale yellow to golden yellow, orange-yellow, or brownish-yellow. Hue, saturation, and tone are important for differentiation.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Vitreous (glassy) for all three, though sapphire can exhibit a sub-adamantine luster due to its high refractive index.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Smooth to conchoidal fracture surfaces when broken. Crystal faces, if present, are typically smooth.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Citrine: Hexagonal prisms with pyramidal terminations. Yellow Sapphire: Hexagonal dipyramids, tabular, or prismatic. Cubic Zirconia: Typically faceted into various gem cuts, rarely found as raw crystals outside of laboratory settings, but would be isometric.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Citrine: None. Yellow Sapphire: No true cleavage, but exhibits parting along basal planes and rhombohedral planes. Cubic Zirconia: None.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Citrine: Hydrothermal veins, pegmatites, and alluvial deposits. Yellow Sapphire: Metamorphic rocks (e.g., marble, gneiss), igneous rocks (e.g., basalt), and secondary alluvial deposits. Cubic Zirconia: Exclusively synthetic, formed in controlled laboratory environments.

Key Facts

Hardness

Citrine: 7; Cubic Zirconia: 8-8.5; Yellow Sapphire: 9 (Mohs scale)

Specific Gravity

Citrine: 2.65; Yellow Sapphire: 4.00; Cubic Zirconia: 5.6-6.0

Crystal System

Citrine: Trigonal; Yellow Sapphire: Trigonal; Cubic Zirconia: Isometric

Color

Pale yellow to golden yellow, orange-yellow, brownish-yellow

Luster

Vitreous (glassy) to sub-adamantine

Transparency

Transparent to translucent

Fracture

Conchoidal

Cleavage

Citrine: None; Yellow Sapphire: No true cleavage, but parting; Cubic Zirconia: None

Composition

Citrine: Silicon dioxide (SiO2); Yellow Sapphire: Aluminum oxide (Al2O3); Cubic Zirconia: Zirconium dioxide (ZrO2)

Physical characteristics

• Crystal Habit: Citrine: Prismatic, often terminated. Yellow Sapphire: Tabular, prismatic, bipyramidal. Cubic Zirconia: Typically faceted, rarely as raw isometric crystals.
• Cleavage Type: Citrine: Absent. Yellow Sapphire: Parting on {0001} and {1011}. Cubic Zirconia: Absent.
• Fracture Type: Conchoidal
• Tenacity: Brittle
• Luster Type: Vitreous to sub-adamantine

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