Sapphirine is a rare magnesium-aluminum silicate typically found in high-grade metamorphic terrains. Collectors prize it for its range of blue to greenish-blue hues, though it is usually opaque to translucent in most localities.

Hardness

7.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent to translucent

mineralrare

Sapphirine

Hardness: 7.5
Luster: Vitreous
Streak: White
Transparency: Transparent to translucent

Is this sapphirine?

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 sapphirine with a known reference. Sapphirine sits at Mohs 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. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: blue, bluish gray, greenish gray, green.
5
Look at form & habit
Crystal system: triclinic. Typical habit: granular, tabular.

Often confused with

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

How to tell apart: Corundum is the harder of the two (Mohs 9 vs. 7.5); luster reads vitreous on Sapphirine and adamantine to vitreous; pearly on partings on Corundum.

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Often found alongside sapphirine

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

All properties

Chemical formula: (Mg,Al)₈(Al,Si)₆O₂₀
Mohs hardness: 7.5
Density: 3.40-3.58 g/cm³
Colors: Blue Bluish gray Greenish gray Green
Streak: White
Luster: Vitreous
Transparency: Transparent to translucent
Crystal system: Triclinic
Crystal habit: Granular, tabular
Cleavage: Fair on {010}, poor on {001}, {100}
Rarity: Rare
Uses: Collector, Scientific research
Host rock: In high-temperature metamorphic rocks or xenoliths with abundant aluminum and magnesium and low silicon

Where rockhounds find sapphirine

Classic worldwide localities

Cortland complex, Westchester Co., New York, USA
Fisken½sset, Greenland
Wilson Lake, Labrador, Newfoundland, Canada
Sakena, Vorokafotra, Bekily, Anjamiary, and Betroka, Madagascar
Blinkwater, near Messina, Transvaal, South Africa
Mautia Hill, Tanzania

Field-hunting tip

Where it forms: In high-temperature metamorphic rocks or xenoliths with abundant aluminum and magnesium and low silicon. If you start seeing sillimanite, kyanite, cordierite in float, you are in the right ground. Typical habit: granular, tabular. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify sapphirine?+

Mohs hardness is 7.5. Luster: vitreous. The streak is white. Common colors include blue, bluish gray, greenish gray, green.

Where is sapphirine found?+

Notable localities include Cortland complex, Westchester Co., New York, USA; Fisken½sset, Greenland; Wilson Lake, Labrador, Newfoundland, Canada; Sakena, Vorokafotra, Bekily, Anjamiary, and Betroka, Madagascar; Blinkwater, near Messina, Transvaal, South Africa.

What rocks look like sapphirine?+

Sapphirine is most often confused with Kyanite, Spinel, Corundum. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with sapphirine?+

Sapphirine commonly co-occurs with Sillimanite, Kyanite, Cordierite, Kornerupine, Corundum, Surinamite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does sapphirine form in?+

Where it forms: In high-temperature metamorphic rocks or xenoliths with abundant aluminum and magnesium and low silicon. Working float back to the host body is the standard way to chase a fresh occurrence.

What is sapphirine used for?+

Sapphirine is used in collector, scientific research.

Find sapphirine on the map

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