Hafnon is a rare silicate mineral that is structurally identical to zircon but with hafnium as the dominant metal. It is typically found in highly evolved granite pegmatites and is prized by collectors for its extreme density and high refractive index. Specimens are usually very small, often occurring as microscopic inclusions or tiny tetragonal crystals.
Is this hafnon?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch hafnon with a known reference. Hafnon sits at Mohs 7.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: gray white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to adamantine.
- 4Match the color rangeCompare against the expected color range: colorless, brownish, yellow.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: prismatic crystals.
Often confused with
Hafnon vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Hafnon leaves gray white, Zircon leaves white.
How to tell apart: Hafnon is noticeably harder (Mohs 7.5 vs. 4.5-5); streak differs, so Hafnon leaves gray white, Thorite leaves light orange to dark brown.
Often found alongside hafnon
Minerals reported to co-occur with hafnon. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- HfSiO₄
- Mohs hardness
- 7.5
- Density
- 6.97 g/cm³
- Streak
- Gray white
- Luster
- Vitreous to adamantine
- Transparency
- Transparent to translucent
- Crystal system
- Tetragonal
- Crystal habit
- Prismatic crystals
- Cleavage
- Indistinct
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In tantalum-bearing granite pegmatites (Zambézia district, Mozambique); in a weathered pegmatite (Mt. Holland, Western Australia)
Where rockhounds find hafnon
Classic worldwide localities
- Morro Conco, Moneia, and Muiâne mines, Morrua area, Zambézia district, Mozambique
- Bikita, Zimbabwe
- Mt. Holland, Western Australia
Field-hunting tip
Where it forms: In tantalum-bearing granite pegmatites (Zambézia district, Mozambique); in a weathered pegmatite (Mt. Holland, Western Australia). If you start seeing cookeite, albite, quartz in float, you are in the right ground. Typical habit: prismatic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
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Find hafnon on the map
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