Sanmartinite is a very rare zinc tungstate mineral that typically appears as yellow to yellowish-brown tabular crystals. It is primarily identified by its distinct adamantine luster and its association with hydrothermal vein deposits, occurring most notably in Argentina.
Is this sanmartinite?
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 sanmartinite with a known reference. Sanmartinite sits at Mohs 4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Sanmartinite leaves a yellowish-white streak.
- 3Read the lusterHold the specimen under a strong light. Sanmartinite typically shows a adamantine luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellowish-brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals.
Often confused with
Sanmartinite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Sanmartinite leaves yellowish-white, Wolframite leaves dark brown to black; luster reads adamantine on Sanmartinite and submetallic to metallic on Wolframite.
How to tell apart: Streak differs, so Sanmartinite leaves yellowish-white, Scheelite leaves white; luster reads adamantine on Sanmartinite and vitreous on Scheelite.
Often found alongside sanmartinite
Minerals reported to co-occur with sanmartinite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- ZnWO₄
- Mohs hardness
- 4
- Density
- 6.57 g/cm³
- Colors
- Streak
- Yellowish-white
- Luster
- Adamantine
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals
- Cleavage
- Perfect On {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Quartz Veins
- Typical price
- $100-500 per specimen
Where rockhounds find sanmartinite
Classic worldwide localities
- San Luis Province, Argentina
- La Rioja, Argentina
Field-hunting tip
Look in hydrothermal quartz veins country, the host setting where sanmartinite typically forms. If you start seeing quartz, muscovite, fluorite in float, you are in the right ground. Field specimens usually show a tabular crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find sanmartinite on the map
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