Rounded vs Split-Face Sauna Stones: Which Is Best for Your Heater?

Choosing the right sauna stones is just as important as selecting your sauna heater. Whether you're using a traditional electric, wood-burning, or modern design heater like HUUM or Harvia, the stone shape and material directly affect steam quality, heater longevity, and heat-up times.

In this article, we’ll break down the differences between rounded sauna stones and split-face (jagged) stones—and help you determine which is best for your sauna setup.

Split-Face Sauna Stones (Jagged)

Split-face stones are sharp-edged, rough-cut stones (usually olivine diabase) that stack tightly and create high surface contact. This makes them ideal for producing strong, fast steam (“löyly”).

• Best for: Electric heaters with heating elements running through the stones (Harvia KIP, Cilindro, Club, Virta)
• Heat Transfer: Excellent—high surface area speeds up heat-up time
• Steam Production: Sharp edges create intense bursts of steam when water is poured
• Maintenance: May require replacement more frequently due to cracking or fragmentation

→ Shop Harvia Split-Face Sauna Stones (5–10cm)

Rounded Sauna Stones

Rounded sauna stones are tumbled smooth for gentler heat release and softer steam. They are typically made from high-density olivine and are ideal for exposed-style sauna heaters like HUUM.

• Best for: Exposed heater designs (HUUM DROP, HIVE, CLIFF, STEEL, Saunum, Harvia Spirit)
• Steam Quality: Softer, longer-lasting steam
• Air Circulation: Better airflow between stones helps prevent overheating
• Longevity: Last longer than split-face and are less prone to cracking

→ Shop Harvia Rounded Olivine Sauna Stones (2–4")

→ Shop HUUM Rounded Sauna Heater Stones

Performance Comparison: Rounded vs Split-Face

Which Sauna Stone Should You Choose?

• Choose Split-Face Stones if you want fast heat-up times and strong steam output, especially in traditional electric or wood-fired heaters like Harvia or Saunum.
• Choose Rounded Stones if you're using a design heater like HUUM and prefer smooth, luxurious steam with better air circulation.

Pro Tip: Always follow your heater manufacturer’s stone recommendations to ensure proper performance and avoid damaging the elements.

→ Browse All Sauna Stones