Goyazite is a strontium aluminum phosphate member of the alunite supergroup, often found as small, sharp, rhombohedral crystals. It is most frequently encountered by collectors in diamond-bearing gravels or as an accessory mineral in hydrothermal veins. Because its appearance can be very similar to other phosphate group minerals, positive identification often requires chemical testing.
Is this goyazite?
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 goyazite with a known reference. Goyazite sits at Mohs 5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Goyazite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Goyazite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, yellow, pink, brown.
- 5Look at form & habitCrystal system: trigonal. Typical habit: rhombohedral crystals, sometimes tabular or pseudocubic.
Often confused with
Goyazite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside goyazite
Minerals reported to co-occur with goyazite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- SrAl₃(PO₄)₂(OH)₅·H₂O
- Mohs hardness
- 5
- Density
- 3.27-3.32 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Rhombohedral Crystals, Sometimes Tabular or Pseudocubic
- Cleavage
- Distinct On {0001}
- Rarity
- Uncommon
- Uses
- Collector, Mineralogical Research
- Host rock
- Hydrothermal Veins, Pegmatites, And Aluminum-rich Metamorphic Rocks
- Typical price
- $20-150 depending on crystal size and matrix quality
Where rockhounds find goyazite
Classic worldwide localities
- Minas Gerais, Brazil
- Diamantina, Brazil
- Mount Bischoff, Tasmania
- Binnental, Switzerland
Field-hunting tip
Look in hydrothermal veins, pegmatites, and aluminum-rich metamorphic rocks country — that is the host setting where goyazite typically forms. If you start seeing lazurite, pyrite, quartz in float, you are in the right ground. Field specimens usually show a rhombohedral crystals, sometimes tabular or pseudocubic habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify goyazite?+
Where is goyazite found?+
How much is goyazite worth?+
What rocks look like goyazite?+
What minerals are found with goyazite?+
What kind of rock does goyazite form in?+
What is goyazite used for?+
Find goyazite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
