Hydroterskite is a rare cyclosilicate mineral found primarily in alkaline igneous environments of the Kola Peninsula in Russia. It is typically found as small, platy crystals associated with other rare zirconium silicates within pegmatitic dikes. Collectors often seek it out as an exotic addition to suites of Russian alkaline minerals.
Is this hydroterskite?
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 hydroterskite with a known reference. Hydroterskite sits at Mohs 4.5-5, 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: pale gray.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: platy crystals, tabular.
Often confused with
Hydroterskite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside hydroterskite
Minerals reported to co-occur with hydroterskite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂ZrSi₆O₁₂(OH)₆
- Mohs hardness
- 4.5-5
- Density
- 2.57 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Platy crystals, tabular
- Cleavage
- Good on ‘the prismatic planes’
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Formed in cavities in a phonolite sill, by post-magmatic hydrothermal processes
Where rockhounds find hydroterskite
Classic worldwide localities
- Saint-Amable sill, Demix-Varennes quarry, near Varennes, Québec, Canada
Field-hunting tip
Where it forms: Formed in cavities in a phonolite sill, by post-magmatic hydrothermal processes. If you start seeing manganoneptunite, aegirine, analcime in float, you are in the right ground. Typical habit: platy crystals, tabular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify hydroterskite?+
Where is hydroterskite found?+
What rocks look like hydroterskite?+
What minerals are found with hydroterskite?+
What kind of rock does hydroterskite form in?+
What is hydroterskite used for?+
Find hydroterskite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
