Kainosite-(Y) is a rare yttrium-calcium silicate that typically forms as translucent, prismatic orthorhombic crystals. It is highly prized by micromounters and advanced collectors for its distinct bright yellow fluorescence under short-wave ultraviolet light, often found in alkaline pegmatites or associated with hydrothermal alteration.
Is this kainosite-(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 kainosite-(y) with a known reference. Kainosite-(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: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to resinous.
- 4Match the color rangeCompare against the expected color range: yellow, brown, colorless, green yellow, light yellow brown.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: prismatic, wheat sheaf.
Often confused with
Kainosite-(Y) vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads vitreous to resinous on Kainosite-(Y) and adamantine to resinous on Titanite.
How to tell apart: Zircon is the harder of the two (Mohs 7.5 vs. 5-6).
How to tell apart: Streak differs, so Kainosite-(Y) leaves white, Epidote leaves grayish white.
Often found alongside kainosite-(y)
Minerals reported to co-occur with kainosite-(y). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₂Y₂(SiO₃)₄(CO₃)·H₂O
- Mohs hardness
- 5-6
- Density
- 3.52 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous to resinous
- Transparency
- Transparent to translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Prismatic, wheat sheaf
- Cleavage
- Good on {110}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In vugs in pegmatites in granites and alkalic complexes
Where rockhounds find kainosite-(y)
Classic worldwide localities
- Cotopaxi, Fremont Co., Colorado, USA
- Pass, Okanogan Co., Washington, USA
- East of Porthill, Boundary Co., Idaho, USA
- Igeltjern, on Hitterö Island, Flekkefjord, Norway
- Ko mine, Nordmark, Värmland, Sweden
- Grubhorn, Baltschiedertal, Valais, Switzerland
Field-hunting tip
Where it forms: In vugs in pegmatites in granites and alkalic complexes. If you start seeing chamosite, pyrite, quartz in float, you are in the right ground. Typical habit: prismatic, wheat sheaf. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify kainosite-(y)?+
Where is kainosite-(y) found?+
Is kainosite-(y) safe to handle?+
What rocks look like kainosite-(y)?+
What minerals are found with kainosite-(y)?+
What kind of rock does kainosite-(y) form in?+
What is kainosite-(y) used for?+
Find kainosite-(y) on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
