Kogarkoite is a rare sodium sulfate fluoride mineral found primarily in hyper-alkaline igneous environments. It typically occurs as colorless or white tabular crystals that are highly soluble in water, requiring care in handling and storage to prevent degradation.
Is this kogarkoite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch kogarkoite with a known reference. Kogarkoite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to dull.
- 4Match the color rangeCompare against the expected color range: colorless, white, light blue.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: earthy, encrustations, pseudo hexagonal.
Often confused with
Kogarkoite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside kogarkoite
Minerals reported to co-occur with kogarkoite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₃(SO₄)F
- Mohs hardness
- 3.5
- Density
- 2.66 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous to dull
- Transparency
- Transparent to translucent
- Crystal system
- Monoclinic
- Crystal habit
- Earthy, encrustations, pseudo hexagonal
- Cleavage
- None
- Fluorescence
- Pale blue under SW UV; white under LW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A sublimate from steam around a hot spring (Hortense Hot Spring, Colorado, USA); in nepheline syenite pegmatite veins in a differentiated alkalic massif (Mt. Alluaiv, Kola Peninsula, Russia)
Where rockhounds find kogarkoite
Classic worldwide localities
- Hortense Hot Spring and at Wright’s Well, Chalk Creek, west of Buena Vista, Chaffee Co., Colorado, USA
- Point of Rocks, Colfax Co., New Mexico, USA
- Mont Saint-Hilaire, Quebec, Canada
- Mts. Alluaiv and Kedykverpakhk, Lovozero massif, Kola Peninsula, Russia
- Lake Magadi, Kenya
- Lake Natron, Tanzania
Field-hunting tip
Where it forms: A sublimate from steam around a hot spring (Hortense Hot Spring, Colorado, USA); in nepheline syenite pegmatite veins in a differentiated alkalic massif (Mt. Alluaiv, Kola Peninsula, Russia). If you start seeing burkeite, trona, halite in float, you are in the right ground. Typical habit: earthy, encrustations, pseudo hexagonal. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify kogarkoite?+
Where is kogarkoite found?+
What rocks look like kogarkoite?+
What minerals are found with kogarkoite?+
What kind of rock does kogarkoite form in?+
What is kogarkoite used for?+
Find kogarkoite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
