Kannanite is a rare, magnesium-rich variety of the tourmaline group, primarily recognized by its distinct blue to blue-green color. It typically forms elongated, heavily striated prismatic crystals and is primarily sourced from pegmatite deposits.

Hardness

7-7.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareTourmaline Group family

Kannanite

Hardness: 7-7.5
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this kannanite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch kannanite with a known reference. Kannanite sits at Mohs 7-7.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Kannanite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Kannanite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: blue, blue-green, green.
5
Look at form & habit
Crystal system: trigonal. Typical habit: prismatic crystals with striated faces.

Often confused with

Kannanite vs. its common look-alikes — and how to tell them apart in the field.

Often found alongside kannanite

Minerals reported to co-occur with kannanite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: Na(Mg₂Al)₆(Si₆O₁₈)(BO₃)₃(OH)₃(OH)
Mohs hardness: 7-7.5
Density: 3.0-3.2 g/cm³
Colors: Blue Blue-green Green
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Trigonal
Crystal habit: Prismatic Crystals with Striated Faces
Cleavage: Indistinct
Rarity: Rare
Uses: Gemstone, Collector
Host rock: Pegmatites
Typical price: $100-2000 per carat for gem quality

Where rockhounds find kannanite

Classic worldwide localities

Kannan, Sri Lanka
Madagascar
Brazil

Field-hunting tip

Look in pegmatites country — that is the host setting where kannanite typically forms. If you start seeing quartz, feldspar, mica in float, you are in the right ground. Field specimens usually show a prismatic crystals with striated faces habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify kannanite?+

Mohs hardness is 7-7.5. It typically shows a vitreous luster. The streak is white. Common colors include blue, blue-green, green.

Where is kannanite found?+

Notable localities include Kannan, Sri Lanka; Madagascar; Brazil.

How much is kannanite worth?+

Typical asking prices fall in the range of $100-2000 per carat for gem quality. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like kannanite?+

Kannanite is most often confused with Indicolite, Elbaite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with kannanite?+

Kannanite commonly co-occurs with Quartz, Feldspar, Mica. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does kannanite form in?+

Kannanite typically forms in pegmatites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is kannanite used for?+

Kannanite is used in gemstone, collector.

Find kannanite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.