Kona Dolomite is a stromatolitic dolostone from the Chocolay Group of the Marquette Range Supergroup, named for the Kona Hills southwest of Marquette, Michigan. It is Paleoproterozoic, about 2.20 to 2.29 billion years old, and its cryptalgal laminations are layered structures built by mats of cyanobacteria in shallow-water marine to supratidal settings. The unit also includes silicified dolostone, quartzite, argillite and slaty dolostone. Its color variation and ability to take a polish make it popular with rockhounds and lapidarists.
Is this kona dolomite?
2-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Read the textureLook at a fresh break with a hand lens. Texture: Stromatolitic, with cryptalgal laminations.
- 2Pick out the mineralsComposition: Dolostone, silicified dolostone and stromatolitic dolostone, with quartzite, argillite and slaty dolostone. Identify the two or three most abundant grains.
All properties
- Uses
- Lapidary, Collector
- Host rock
- Kona Dolomite, Chocolay Group, lower Marquette Range Supergroup; shallow-water marine to supratidal deposits
- Texture
- Stromatolitic, with cryptalgal laminations
- Composition
- Dolostone, silicified dolostone and stromatolitic dolostone, with quartzite, argillite and slaty dolostone
Where rockhounds find kona dolomite
1 mapped spotsClassic worldwide localities
- Vicinity of Marquette, Michigan
- Lindberg Quarry, Marquette, Michigan
Field-hunting tip
Where it forms: Kona Dolomite, Chocolay Group, lower Marquette Range Supergroup; shallow-water marine to supratidal deposits. In the U.S., the densest reported localities are in Michigan. Start trip planning there.
Common questions
Where is kona dolomite found?+
Can I find kona dolomite in the United States?+
What kind of rock does kona dolomite form in?+
What is kona dolomite used for?+
Find kona dolomite on the map
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