Strontiojoaquinite is an extremely rare member of the joaquinite group primarily found in the unique hydrothermal environments of the Benitoite Gem Mine. It typically forms small, wedge-shaped or tabular brown crystals that are almost exclusively identified through professional analysis due to their strong resemblance to other members of the joaquinite group.

Hardness

5.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Semitransparent

mineralrareJoaquinite Group family

Strontiojoaquinite

Hardness: 5.5
Luster: Vitreous
Streak: White
Transparency: Semitransparent

Is this strontiojoaquinite?

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 strontiojoaquinite with a known reference. Strontiojoaquinite sits at Mohs 5.5, 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: green, yellow brown, yellow green.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: tabular crystals, wedge-shaped.

Often found alongside strontiojoaquinite

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

All properties

Chemical formula: (Na,Fe)₂Ba₂Sr₂Ti₂(SiO₃)₈(O,OH)₂·H₂O
Mohs hardness: 5.5
Density: 3.68 g/cm³
Colors: Green Yellow brown Yellow green
Streak: White
Luster: Vitreous
Transparency: Semitransparent
Crystal system: Monoclinic
Crystal habit: Tabular crystals, wedge-shaped
Cleavage: Good on {001}
Rarity: Rare
Uses: Collector
Host rock: In a metamorphosed and metasomatized basalt lens in serpentinite (Mina Numero Uno, California, USA); in veins cutting metagraywacke (prospect, San Benito Co., California, USA)

Where rockhounds find strontiojoaquinite

Classic worldwide localities

Mina Numero Uno, south side of Clear Creek, USA
A prospect about three km southwest of San Benito Mountain, San Benito Co., California, USA

Field-hunting tip

Where it forms: In a metamorphosed and metasomatized basalt lens in serpentinite (Mina Numero Uno, California, USA); in veins cutting metagraywacke (prospect, San Benito Co., California, USA). If you start seeing joaquinite-, neptunite, natrolite in float, you are in the right ground. Typical habit: tabular crystals, wedge-shaped. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify strontiojoaquinite?+

Mohs hardness is 5.5. Luster: vitreous. The streak is white. Common colors include green, yellow brown, yellow green.

Where is strontiojoaquinite found?+

Notable localities include Mina Numero Uno, south side of Clear Creek, USA; A prospect about three km southwest of San Benito Mountain, San Benito Co., California, USA.

What minerals are found with strontiojoaquinite?+

Strontiojoaquinite commonly co-occurs with Joaquinite-, Neptunite, Natrolite, Albite, Actinolite, Crossite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does strontiojoaquinite form in?+

Where it forms: In a metamorphosed and metasomatized basalt lens in serpentinite (Mina Numero Uno, California, USA); in veins cutting metagraywacke (prospect, San Benito Co., California, USA). Working float back to the host body is the standard way to chase a fresh occurrence.

What is strontiojoaquinite used for?+

Strontiojoaquinite is used in collector.

Find strontiojoaquinite on the map

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