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, 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.