Bonaccordite is an extremely rare borate mineral known primarily from the Bon Accord nickel deposit in South Africa. It typically occurs as dark brown to black acicular needles or fibrous aggregates, often intergrown with other nickel-bearing minerals. Due to its limited occurrence, it is highly sought after by advanced systematic mineral collectors.
Is this bonaccordite?
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 bonaccordite with a known reference. Bonaccordite sits at Mohs 6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Bonaccordite leaves a brown streak.
- 3Read the lusterHold the specimen under a strong light. Bonaccordite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: dark brown, brownish black.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: acicular crystals, fibrous aggregates.
Often confused with
Bonaccordite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Bonaccordite is noticeably harder (Mohs 6 vs. 5); streak differs — Bonaccordite leaves brown, Ludwigite leaves black; luster reads vitreous on Bonaccordite and submetallic on Ludwigite.
How to tell apart: Bonaccordite is noticeably harder (Mohs 6 vs. 5); streak differs — Bonaccordite leaves brown, Vonsenite leaves black; luster reads vitreous on Bonaccordite and submetallic on Vonsenite.
Often found alongside bonaccordite
Minerals reported to co-occur with bonaccordite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ni₂FeBO₅
- Mohs hardness
- 6
- Density
- 4.67 g/cm³
- Colors
- Streak
- Brown
- Luster
- Vitreous
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Acicular Crystals, Fibrous Aggregates
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Nickel-rich Ultramafic Xenoliths
- Typical price
- $50-300 per specimen
Where rockhounds find bonaccordite
Classic worldwide localities
- Bon Accord, Mpumalanga, South Africa
Field-hunting tip
Look in nickel-rich ultramafic xenoliths country — that is the host setting where bonaccordite typically forms. If you start seeing trevorite, willemseite, bunsenite in float, you are in the right ground. Field specimens usually show a acicular crystals, fibrous aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify bonaccordite?+
Where is bonaccordite found?+
How much is bonaccordite worth?+
What rocks look like bonaccordite?+
What minerals are found with bonaccordite?+
What kind of rock does bonaccordite form in?+
What is bonaccordite used for?+
Find bonaccordite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
