Olivine Diabase: The Standard Sauna Stone
Olivine diabase is the most popular sauna stone for good reason: dense, heat-stable and durable. Here is why it works and how it compares to alternatives.
The short answer
Olivine diabase is the most widely used sauna stone because it is dense, low-porosity and highly resistant to thermal shock. It stores a lot of heat, survives years of heat-and-douse cycling, and makes a strong, even löyly.
If you buy stones sold specifically for saunas, chances are they are olivine diabase. It has become the default sauna stone across the industry, and the reasons are entirely practical.
Why it works so well
- Density. It stores a large amount of heat for its size, which is exactly what makes good löyly.
- Low porosity. Very little water gets trapped inside, so it resists the cracking that ruins porous stones.
- Thermal-shock resistance. It tolerates the rapid heating and cold-water dousing of sauna use without splitting.
- Durability. It lasts, typically 1–3 years of regular use before needing a refresh.
How it compares
| Stone | Verdict |
|---|---|
| Olivine diabase | Excellent — the standard |
| Peridotite | Excellent — very dense, see our peridotite guide |
| Dense basalt | Good if genuinely non-porous |
| Granite | Risky — quartz can fracture |
| River / landscape rock | Avoid — may trap water and burst |
Our overview of the best sauna stones covers the full field.
Getting the most from it
Olivine diabase is inexpensive and widely available, and it is hard to go wrong with it. Buy stones sold for sauna use, load them well, and refresh the pile when they start to crumble — and the heart of your sauna will keep making soft, strong steam for years.
Getting olivine diabase to perform
The stone itself sets the ceiling on performance, but loading is what actually delivers the löyly. Rinse new olivine diabase to wash off quarry dust, then build the pile with the largest stones at the base for thermal mass and airflow, grading up to smaller stones on top where the water lands. Keep the whole pile loose, with visible air gaps, so heat distributes evenly and water flashes cleanly to steam rather than running through.
Because olivine diabase is dense, mind your heater rated stone capacity by weight and do not overfill past it — an overpacked pile chokes airflow and, on electric heaters, traps heat around the elements. Inspect the stones once or twice a year, discard any that have cracked or crumbled, and clear the grit they shed. Treated this way, an inexpensive load of olivine diabase gives years of soft, strong steam, which is exactly why it has become the industry standard sauna stone.
Part of the appeal of olivine diabase is simply how foolproof it is. It is inexpensive, sold everywhere that sells saunas, and hard to go wrong with — buy it as sauna stone, rinse it, load it loosely to capacity, and refresh it when it eventually crumbles. For the vast majority of home saunas, it is all the stone you will ever need, which is exactly how it became the default across the industry.
Frequently asked questions
What is olivine diabase?
A dense, dark igneous rock that is the most popular sauna stone. Its density, low porosity and resistance to thermal shock make it store heat well and survive years of sauna use.
Why is olivine diabase used for sauna stones?
Because it stores a lot of heat, traps very little water (so it resists cracking), and tolerates repeated rapid heating and cold-water dousing better than most rocks.
How long do olivine diabase stones last?
Typically 1–3 years of regular use before they should be refreshed. Inspect once or twice a year and replace any that have cracked or crumbled.
Is olivine diabase better than basalt for saunas?
Olivine diabase is the reliable standard; dense, non-porous basalt also works well. The key is genuine density and low porosity — avoid porous or layered stone.
Where do you buy olivine diabase sauna stones?
From sauna suppliers and heater retailers, sold specifically as sauna stones. Buying stones intended for saunas ensures the right composition and avoids the risks of random rock.
Do you need to wash olivine diabase before use?
Yes — rinse new stones to remove quarry dust and grit before loading, so your first löyly is clean and the airflow through the pile stays open. This applies to any new sauna stone.
Can you overfill a heater with olivine diabase?
Yes. Because it is dense, mind the heater rated capacity by weight and do not exceed it — an overpacked pile chokes airflow and, on electric heaters, traps heat around the elements, shortening their life.
How do you keep olivine diabase performing well?
Load it loosely, largest at the base and smaller on top, and inspect it once or twice a year, discarding cracked stones and clearing grit. Fresh, loosely stacked stones keep the löyly soft and strong.
Is olivine diabase a good choice for a first sauna?
Yes — it is inexpensive, widely available, and hard to go wrong with. For the vast majority of home saunas it is all the stone you need: buy it as sauna stone, rinse it, load it loosely to capacity, and refresh it when it crumbles.
