Itsiite is an extremely rare borosilicate mineral discovered in the Itsi Mountains of Yukon, Canada. It typically appears as small, colorless to light blue tabular crystals found within skarn deposits associated with boron-rich hydrothermal activity.
Is this itsiite?
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 itsiite with a known reference. Itsiite sits at Mohs 5.5, 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, medium greenish blue.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: tabular crystals.
Often confused with
Itsiite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside itsiite
Minerals reported to co-occur with itsiite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ba₂Ca(BSi₂O₇)₂
- Mohs hardness
- 5.5
- Density
- 3.644 g/cm³
- Colors
- ColorlessMedium greenish blue
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Tetragonal
- Crystal habit
- Tabular crystals
- Cleavage
- Perfect on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In low-temperature, late-stage hydrothermal veins cutting a contact-metamorphic, Ba-rich skarn deposit adjacent to quartz monzonite
Where rockhounds find itsiite
Classic worldwide localities
- Gun claim, 4 km SE of Wilson Lake, south of the Itsi Range, Yukon Territory, Canada
Field-hunting tip
Where it forms: In low-temperature, late-stage hydrothermal veins cutting a contact-metamorphic, Ba-rich skarn deposit adjacent to quartz monzonite. If you start seeing cerchiaraite-, diopside, pyrite in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify itsiite?+
Where is itsiite found?+
What rocks look like itsiite?+
What minerals are found with itsiite?+
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Find itsiite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
