Ecandrewsite is a rare zinc-rich member of the ilmenite group, primarily occurring in high-grade metamorphic terrains. It is typically found as opaque, black granular masses and is notoriously difficult to distinguish from other ilmenite-group minerals without chemical analysis. Collectors prize it as a rare mineralogical curiosity from zinc-rich ore bodies.
Is this ecandrewsite?
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 ecandrewsite with a known reference. Ecandrewsite 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: dark brown to black.
- 3Read the lusterHold the specimen under a strong light. Luster: submetallic.
- 4Match the color rangeCompare against the expected color range: black, brownish black, dark brown.
- 5Look at form & habitCrystal system: trigonal. Typical habit: granular, tabular.
Often confused with
Ecandrewsite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Ecandrewsite leaves dark brown to black, Ilmenite leaves black to reddish brown; luster reads submetallic on Ecandrewsite and metallic to submetallic on Ilmenite.
How to tell apart: Streak differs, so Ecandrewsite leaves dark brown to black, Geikielite leaves purplish brown.
How to tell apart: Streak differs, so Ecandrewsite leaves dark brown to black, Pyrophanite leaves ocher-yellow, with greenish tinge; luster reads submetallic on Ecandrewsite and metallic to submetallic on Pyrophanite.
Often found alongside ecandrewsite
Minerals reported to co-occur with ecandrewsite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- ZnTiO₃
- Mohs hardness
- 5-5.5
- Density
- 4.98-4.99 g/cm³
- Streak
- Dark brown to black
- Luster
- Submetallic
- Transparency
- Opaque to translucent
- Crystal system
- Trigonal
- Crystal habit
- Granular, tabular
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In quartz-rich metasediments of the amphibolite-granulite facies (Melbourne Rockwell mine, Australia); in a kyanite-bearing pelitic schist (Death Valley, California, USA)
Where rockhounds find ecandrewsite
Classic worldwide localities
- Black Mountains, Death Valley, Inyo Co., California, USA
- Melbourne Rockwell mine, Little Broken Hill, and the North mine, Broken Hill, New South Wales, Australia
- San Valentin mine, La Unión district, Sierra de Cartegena, Murcia Province, Spain
- Fuzhou, Fujian Province, China
Field-hunting tip
Where it forms: In quartz-rich metasediments of the amphibolite-granulite facies (Melbourne Rockwell mine, Australia); in a kyanite-bearing pelitic schist (Death Valley, California, USA). If you start seeing almandine-spessartine, ferroan gahnite, rutile in float, you are in the right ground. Typical habit: granular, tabular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ecandrewsite?+
Where is ecandrewsite found?+
What rocks look like ecandrewsite?+
What minerals are found with ecandrewsite?+
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Find ecandrewsite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
