Gramaccioliite-(Y) is a rare mineral belonging to the crichtonite group, typically occurring as small, dark, rhombohedral crystals in pegmatite cavities. It is distinguished by its yttrium content and is usually found in highly specialized geological settings like the famous Baveno granite.
Is this gramaccioliite-(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 gramaccioliite-(y) with a known reference. Gramaccioliite-(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. Gramaccioliite-(Y) leaves a brownish black streak.
- 3Read the lusterHold the specimen under a strong light. Gramaccioliite-(Y) typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: black.
- 5Look at form & habitCrystal system: trigonal. Typical habit: rhombohedral crystals.
Often confused with
Gramaccioliite-(Y) vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Gramaccioliite-(Y) leaves brownish black, Crichtonite leaves black; luster reads metallic on Gramaccioliite-(Y) and metallic to dull on Crichtonite.
How to tell apart: Streak differs, so Gramaccioliite-(Y) leaves brownish black, Davidite-(La) leaves black; luster reads metallic on Gramaccioliite-(Y) and submetallic on Davidite-(La).
Often found alongside gramaccioliite-(y)
Minerals reported to co-occur with gramaccioliite-(y). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Pb,Sr)(Y,Mn)Fe³⁺₂(Ti,Fe³⁺)₁₈O₃₈
- Mohs hardness
- 5-6
- Density
- 4.45 g/cm³
- Colors
- Streak
- Brownish Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Trigonal
- Crystal habit
- Rhombohedral Crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Granite Pegmatites
Where rockhounds find gramaccioliite-(y)
Classic worldwide localities
- Baveno, Piedmont, Italy
- Mount Malosa, Zomba District, Malawi
Field-hunting tip
Look in granite pegmatites country, the host setting where gramaccioliite-(y) typically forms. If you start seeing quartz, microcline, albite in float, you are in the right ground. Field specimens usually show a rhombohedral crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify gramaccioliite-(y)?+
Where is gramaccioliite-(y) found?+
Is gramaccioliite-(y) safe to handle?+
What rocks look like gramaccioliite-(y)?+
What minerals are found with gramaccioliite-(y)?+
What kind of rock does gramaccioliite-(y) form in?+
What is gramaccioliite-(y) used for?+
Find gramaccioliite-(y) on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
