Vlasovite is a rare zirconium silicate mineral primarily found in alkaline igneous massifs. Collectors prize it for its distinct orange fluorescence under long-wave ultraviolet light, which helps distinguish it from more common associated minerals.
Is this vlasovite?
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 vlasovite with a known reference. Vlasovite sits at Mohs 6, 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: greasy; highly vitreous to pearly on cleavage surfaces.
- 4Match the color rangeCompare against the expected color range: colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, massive, granular.
Often confused with
Vlasovite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads greasy; highly vitreous to pearly on cleavage surfaces on Vlasovite and vitreous to dull on Eudialyte.
How to tell apart: Quartz is the harder of the two (Mohs 7 vs. 6); luster reads greasy; highly vitreous to pearly on cleavage surfaces on Vlasovite and vitreous; waxy to dull when massive on Quartz.
Often found alongside vlasovite
Minerals reported to co-occur with vlasovite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂ZrSi₄O₁₁
- Mohs hardness
- 6
- Density
- 2.92-2.97 g/cm³
- Colors
- Streak
- White
- Luster
- Greasy; highly vitreous to pearly on cleavage surfaces
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular crystals, massive, granular
- Cleavage
- {010}, good; fh0lg, poor
- Fluorescence
- Strong orange-yellow under SW and LW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A late phase in nepheline syenites, syenitic pegmatites, and along the contact zone of a differentiated alkalic massif (Lovozero massif, Russia)
Where rockhounds find vlasovite
Classic worldwide localities
- Mt. Vavnbed, Lovozero massif, Kola Peninsula, Russia
- Burpala massif, about 120 km north of Lake Baikal, eastern Siberia, Russia
- Green Mountain, Ascension Island, southern Atlantic Ocean
Field-hunting tip
Where it forms: A late phase in nepheline syenites, syenitic pegmatites, and along the contact zone of a differentiated alkalic massif (Lovozero massif, Russia). If you start seeing eudialyte, microcline, albite in float, you are in the right ground. Typical habit: tabular crystals, massive, granular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify vlasovite?+
Where is vlasovite found?+
What rocks look like vlasovite?+
What minerals are found with vlasovite?+
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Find vlasovite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
