Indigo Gabbro is a coarse-grained igneous rock, often trade-named 'Mystic Merlinite', primarily sourced from Madagascar. It is characterized by its deep charcoal-to-indigo base color with swirling inclusions of grey and purple, which take a high polish in lapidary work.
Is this indigo gabbro?
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 indigo gabbro with a known reference. Indigo Gabbro sits at Mohs 6-7 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Indigo Gabbro leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Indigo Gabbro typically shows a submetallic luster.
- 4Match the color rangeCompare against the expected color range: black, dark purple, gray.
- 5Look at form & habitTypical habit: massive.
Often confused with
Indigo Gabbro vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Indigo Gabbro leaves white, Gabbro leaves none; luster reads submetallic on Indigo Gabbro and vitreous on Gabbro.
How to tell apart: Luster reads submetallic on Indigo Gabbro and vitreous on Labradorite.
Often found alongside indigo gabbro
Minerals reported to co-occur with indigo gabbro. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Mohs hardness
- 6-7
- Density
- 2.8-3.1 g/cm³
- Colors
- Streak
- White
- Luster
- Submetallic
- Transparency
- Opaque
- Crystal habit
- Massive
- Cleavage
- None
- Rarity
- Common
- Uses
- Lapidary, Collector, Decorative
- Host rock
- Plutonic Igneous Rock
- Typical price
- $5-50 for slabs and spheres
Where rockhounds find indigo gabbro
Classic worldwide localities
- Madagascar
Field-hunting tip
Look in plutonic igneous rock country — that is the host setting where indigo gabbro typically forms. If you start seeing plagioclase, pyroxene, magnetite in float, you are in the right ground. Field specimens usually show a massive habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find indigo gabbro on the map
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