Zaccariniite is a rare platinum-group mineral typically occurring as microscopic grains within chromite deposits. Collectors rarely encounter it except as micro-inclusions in platinum-group alloy suites found in ophiolitic complexes.
Is this zaccariniite?
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 zaccariniite with a known reference. Zaccariniite sits at Mohs 3.5-4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: gray.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: gray, white with brownish.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: anhedral grains.
Often confused with
Zaccariniite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Sperrylite is the harder of the two (Mohs 6-7 vs. 3.5-4); streak differs, so Zaccariniite leaves gray, Sperrylite leaves black.
How to tell apart: Laurite is the harder of the two (Mohs 7.5 vs. 3.5-4); streak differs, so Zaccariniite leaves gray, Laurite leaves dark gray.
How to tell apart: Hollingworthite is the harder of the two (Mohs >6 vs. 3.5-4); streak differs, so Zaccariniite leaves gray, Hollingworthite leaves grayish-black.
Often found alongside zaccariniite
Minerals reported to co-occur with zaccariniite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- RhNiAs
- Mohs hardness
- 3.5-4
- Density
- 10.09 g/cm³
- Colors
- GrayWhite with brownish
- Streak
- Gray
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Tetragonal
- Crystal habit
- Anhedral grains
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A low temperature mineral formed during alteration of ophiolite, now in heavy-mineral concentrate derived from ophiolitic chromitite
Where rockhounds find zaccariniite
Classic worldwide localities
- Loma Peguera chromitite, Loma Caribe peridotite, Cordillera Central, Dominican Republic
- Koryako-Kamchatskiy region and Nizhny Tagil, Ural-Alaskan chromitites, Urals, Russia
- Chindwin area, Burma, Kazakhstan
- Onverwacht pipe, Bushveld Complex, South Africa, Kazakhstan
- Thetford mine, Quebec, Canada, Kazakhstan
- Vourinos chromitites, Greece, and the Kempirsai chromitites, Kazakhstan
Field-hunting tip
Where it forms: A low temperature mineral formed during alteration of ophiolite, now in heavy-mineral concentrate derived from ophiolitic chromitite. If you start seeing garutiite, hexaferrum, ru-os-ir-fe alloys in float, you are in the right ground. Typical habit: anhedral grains. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify zaccariniite?+
Where is zaccariniite found?+
Is zaccariniite safe to handle?+
What rocks look like zaccariniite?+
What minerals are found with zaccariniite?+
What kind of rock does zaccariniite form in?+
What is zaccariniite used for?+
Find zaccariniite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
