Johachidolite is an extremely rare borate mineral that occurs as small, colorless to white crystals. It is primarily found in highly metamorphosed limestone environments and is highly prized by collectors for its exceptional rarity and clarity.

Hardness

7.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent to translucent

mineralrare

Johachidolite

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

Is this johachidolite?

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 johachidolite with a known reference. Johachidolite 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: colorless, white.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: tabular crystals, massive, granular.

Often confused with

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

Often found alongside johachidolite

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

All properties

Chemical formula: CaAlB₃O₇
Mohs hardness: 7.5
Density: 3.37-3.45 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent to translucent
Crystal system: Orthorhombic
Crystal habit: Tabular crystals, massive, granular
Cleavage: On {201}, a parting
Fluorescence: Blue under SW UV
Rarity: Rare
Uses: Collector, Lapidary
Host rock: In a nepheline dike cutting limestone (Johachido district, North Korea)

Where rockhounds find johachidolite

Classic worldwide localities

Johachido district, Kankyo Hodu Prefecture, North Korea
A cut stone considered of natural origin is attributed to the Mogok region, Myanmar

Field-hunting tip

Where it forms: In a nepheline dike cutting limestone (Johachido district, North Korea). If you start seeing scapolite, diopside, albite in float, you are in the right ground. Typical habit: tabular crystals, massive, granular. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify johachidolite?+

Mohs hardness is 7.5. Luster: vitreous. The streak is white. Common colors include colorless, white.

Where is johachidolite found?+

Notable localities include Johachido district, Kankyo Hodu Prefecture, North Korea; A cut stone considered of natural origin is attributed to the Mogok region, Myanmar.

What rocks look like johachidolite?+

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

What minerals are found with johachidolite?+

Johachidolite commonly co-occurs with Scapolite, Diopside, Albite, Nepheline, Apatite, Phlogopite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does johachidolite form in?+

Where it forms: In a nepheline dike cutting limestone (Johachido district, North Korea). Working float back to the host body is the standard way to chase a fresh occurrence.

What is johachidolite used for?+

Johachidolite is used in collector, lapidary.

Find johachidolite on the map

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