Heliodor Identification Guide
Identifying heliodor, the golden-yellow beryl, by its color, hexagonal crystals, hardness, density, and how to separate it from citrine and other look-alikes.
Read the full Heliodor encyclopedia entry →
What Heliodor Looks Like
Heliodor is the yellow to greenish-yellow and golden variety of beryl (Be₃Al₂Si₆O₁₈), colored by iron. It ranges from pale lemon to rich golden honey, sometimes with a green tint that blurs the line with green beryl. Crystals are typically transparent, glassy, and form long hexagonal (six-sided) prisms with flat terminations and often vertical striations along the prism faces. Luster is vitreous.
- Color: golden-yellow, lemon, honey, greenish-yellow
- Transparency: transparent to translucent
- Luster: vitreous
- Habit: elongated hexagonal prisms, often striated lengthwise
Step-by-Step Field-ID Checklist
- Look at crystal symmetry. A six-sided prism with lengthwise striations is the beryl signature.
- Judge the color. Even, warm golden-yellow without strong zoning fits heliodor.
- Test hardness. Heliodor scratches quartz — a key separator from yellow quartz.
- Heft it. Beryl feels slightly heavier than quartz of the same size.
- Check inclusions. Long hollow tubes parallel to the c-axis are common in beryl.
Key Diagnostic Tests
- Mohs hardness: 7.5–8 — scratches quartz (the decisive test vs. citrine).
- Streak: white.
- Cleavage: imperfect basal; conchoidal fracture.
- Specific gravity: ~2.6–2.9 — a touch heavier than quartz.
- Crystal system: hexagonal.
- Pleochroism: weak (pale yellow / slightly greener) under a dichroscope.
- Acid: no reaction.
Common Look-Alikes and How to Tell Them Apart
- Citrine (yellow quartz): softer (7, does not scratch heliodor), lower SG, and often shows quartz's trigonal habit; heliodor scratches quartz and has hexagonal prisms.
- Yellow sapphire: much harder (9) and denser; scratches heliodor easily.
- Yellow topaz: has one perfect basal cleavage and higher SG (~3.5); beryl lacks strong cleavage and is lighter.
- Golden beryl: essentially the same species — the names overlap, with 'golden beryl' often used for the most saturated yellow.
- Yellow tourmaline: trigonal with rounded triangular cross-section and strong pleochroism; beryl is hexagonal with weak pleochroism.
The make-or-break tests are hardness above quartz and a true hexagonal prism, which together rule out citrine and most yellow imitators.
Where Heliodor Is Found
Heliodor forms in granitic pegmatites. Notable sources include Ukraine (Volyn pegmatites, the classic locality), Brazil (Minas Gerais), Madagascar, Namibia, Russia, Tajikistan, and the United States (Connecticut, Maine).
Quick Field Summary
A transparent, golden-yellow, six-sided prismatic crystal that scratches quartz and feels slightly heavy is heliodor — distinguished from softer citrine, denser topaz and sapphire, and trigonal yellow tourmaline.
Frequently asked questions
How can you tell if it's real heliodor?
Real heliodor is beryl with a hardness of 7.5–8 that scratches quartz, forms six-sided hexagonal prisms often striated lengthwise, and has a specific gravity around 2.7–2.9. Citrine, by contrast, is softer and will not scratch it.
What is the difference between heliodor and citrine?
Heliodor is golden beryl (harder than quartz, hexagonal prisms), while citrine is yellow quartz (Mohs 7, lower density). Heliodor scratches citrine but not vice versa, and their crystal habits differ.
What color is heliodor?
Heliodor ranges from pale lemon and golden-yellow to honey and greenish-yellow, with its color caused by iron in the beryl structure.
Is heliodor the same as golden beryl?
They are essentially the same species — yellow beryl. 'Golden beryl' is often used for the most saturated golden stones, while 'heliodor' may carry a greenish-yellow connotation, but the terms are frequently used interchangeably.
Heliodor identified by the community
Recent Heliodor specimens identified with Rock Identifier.
