Písekite-(Y) is a rare radioactive complex oxide mineral primarily found in rare-earth-element-rich granitic pegmatites. It typically occurs as black to brownish, heavy prismatic crystals and is chemically related to the Euxenite group, often requiring sophisticated analytical techniques for positive identification.
Is this písekite-(y)?
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 písekite-(y) with a known reference. Písekite-(Y) sits at Mohs 5-6, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: yellowish-brown.
- 3Read the lusterHold the specimen under a strong light. Luster: submetallic.
- 4Match the color rangeCompare against the expected color range: black, brown, yellowish-brown.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: prismatic crystals, massive.
Often confused with
Písekite-(Y) vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Písekite-(Y) leaves yellowish-brown, Euxenite-(Y) leaves yellowish, grayish, or reddish brown; luster reads submetallic on Písekite-(Y) and brilliant submetallic, waxy to resinous on fractures on Euxenite-(Y).
How to tell apart: Streak differs, so Písekite-(Y) leaves yellowish-brown, Samarskite-(Y) leaves dark reddish brown to black, yellow-brown; gray when altered; luster reads submetallic on Písekite-(Y) and vitreous to resinous, may be submetallic, splendent; externally dull on Samarskite-(Y).
Often found alongside písekite-(y)
Minerals reported to co-occur with písekite-(y). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Y,As,Ca,Fe,U)(Nb,Ti,Ta)O₄
- Mohs hardness
- 5-6
- Density
- 5.3-5.5 g/cm³
- Streak
- Yellowish-brown
- Luster
- Submetallic
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Prismatic crystals, massive
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- granite pegmatites
Where rockhounds find písekite-(y)
Classic worldwide localities
- Písek, Czech Republic
- Iveland, Norway
- Hittero, Norway
Field-hunting tip
Where it forms: granite pegmatites. If you start seeing monazite, zircon, beryl in float, you are in the right ground. Typical habit: prismatic crystals, massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify písekite-(y)?+
Where is písekite-(y) found?+
Is písekite-(y) safe to handle?+
What rocks look like písekite-(y)?+
What minerals are found with písekite-(y)?+
What kind of rock does písekite-(y) form in?+
What is písekite-(y) used for?+
Find písekite-(y) on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
