Junitoite is a very rare calcium-zinc silicate mineral discovered in the Christmas Mine in Arizona. It typically forms small, clear, tabular, or bladed crystals often associated with willemite in metamorphic skarn deposits.
Is this junitoite?
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 junitoite with a known reference. Junitoite sits at Mohs 4.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: colorless, white.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: tabular crystals.
Often confused with
Junitoite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside junitoite
Minerals reported to co-occur with junitoite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaZn₂Si₂O₇·H₂O
- Mohs hardness
- 4.5
- Density
- 3.5 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent to translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Tabular crystals
- Cleavage
- Good on {100}; poor on {010} and {011}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a retrogressively altered tactite zone, closely related to the breakdown of sphalerite in the ores
Where rockhounds find junitoite
Classic worldwide localities
- Christmas copper mine, Gila Co., Arizona, USA
Field-hunting tip
Where it forms: In a retrogressively altered tactite zone, closely related to the breakdown of sphalerite in the ores. If you start seeing kinoite, apophyllite, calcite in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.
Common questions
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Find junitoite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
