Hyalotekite is a rare lead-rich sorosilicate mineral primarily known for its distinct and intense fluorescence under short-wave UV light. It is typically found in metamorphosed manganese deposits, appearing as massive, vitreous material that is often indistinguishable from associated gangue minerals without UV testing.
Is this hyalotekite?
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 hyalotekite with a known reference. Hyalotekite sits at Mohs 5-5.5, 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 to greasy.
- 4Match the color rangeCompare against the expected color range: white, pearly gray.
- 5Look at form & habitCrystal system: triclinic. Typical habit: crystalline, massive.
Often confused with
Hyalotekite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside hyalotekite
Minerals reported to co-occur with hyalotekite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Ba,Pb,K)₄(Ca,Y)₂(B,Be)₂(Si,B)₂Si₈O₂₈F
- Mohs hardness
- 5-5.5
- Density
- 3.81-3.82 g/cm³
- Colors
- WhitePearly gray
- Streak
- White
- Luster
- Vitreous to greasy
- Transparency
- Transparent in very thin plates
- Crystal system
- Triclinic
- Crystal habit
- Crystalline, massive
- Cleavage
- Easy in two directions at ~90°; indistinct in a third direction in the same zone as the other two
- Fluorescence
- Light brownish orange under SW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Sparingly in feldspar in a metamorphosed Fe{Mn deposit (Långban, Sweden); in reedmergnerite pegmatite in an alkaline massif (Dara-i-Pioz massif, Tajikistan)
Where rockhounds find hyalotekite
Classic worldwide localities
- Långban, Värmland, Sweden
- Dara-i-Pioz massif, Alai Range, Tien Shan, Tajikistan
Field-hunting tip
Where it forms: Sparingly in feldspar in a metamorphosed Fe{Mn deposit (Långban, Sweden); in reedmergnerite pegmatite in an alkaline massif (Dara-i-Pioz massif, Tajikistan). If you start seeing quartz, calcite, hematite in float, you are in the right ground. Typical habit: crystalline, massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify hyalotekite?+
Where is hyalotekite found?+
Is hyalotekite safe to handle?+
What rocks look like hyalotekite?+
What minerals are found with hyalotekite?+
What kind of rock does hyalotekite form in?+
What is hyalotekite used for?+
Find hyalotekite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
