Maifan Stone: What It Is, How It Works, and How to Use It

Maifan stone is a naturally occurring mineral rock used in water filtration to remineralise and improve the quality of drinking water. It’s one of the mineral stages in our 8-stage KDF benchtop water filters — here’s a clear explanation of what it is and what it actually does.

Browse our maifan stones or see our Benchtop Water Filters Guide for more detail on how our filter systems work.

What Is Maifan Stone?

Maifan stone (also called medical stone or Chinese medical stone) is a naturally occurring mineral rock composed primarily of plagioclase feldspar, hornblende, biotite, and various silicates. It contains a broad spectrum of trace minerals including calcium, magnesium, zinc, iron, copper, selenium, and silicon.

It’s been used in traditional Chinese medicine for centuries and is now widely used in water filtration as a natural remineralisation medium — particularly in multi-stage benchtop and gravity-fed filter systems.

What Does Maifan Stone Do to Water?

• Releases trace minerals — calcium, magnesium, zinc, iron, and other beneficial minerals dissolve slowly into the water
• Adsorbs contaminants — the porous surface adsorbs heavy metals and some impurities from the water
• Stabilises pH — maifan stone has amphoteric properties, helping to buffer water towards a neutral pH
• Improves taste — the mineral addition gives water a cleaner, more balanced flavour

Remineralisation begins approximately 8 minutes after the stone first contacts water.

Important note: maifan stone is a remineralisation medium, not a primary filter. It doesn’t remove chlorine, fluoride, or bacteria. In our 8-stage filter systems, it works alongside KDF, activated carbon, and ceramic stages that handle contaminant removal.

How to Use Maifan Stones

Maifan stones can be used in a glass or ceramic water vessel, or as a stage within a multi-stage filter system:

• Place one or more stones in a clean glass or ceramic container with your drinking water
• Leave for at least 8 minutes before drinking — longer contact time increases mineral release
• For best results, use with pre-filtered water (the stones work on mineralisation, not contaminant removal)
• They can also be placed in a 15–20L water cooler bottle for ongoing mineralisation

Cleaning and Lifespan

Maifan stones require minimal maintenance compared to other filter media:

• Every 6 months: remove the stone and boil in clean water for 20 minutes to sanitise
• Lifespan: typically 1–3 years depending on water quality and usage frequency
• Signs of erosion are normal — they indicate the stone has been actively adsorbing contaminants. Replace when the stone has visibly reduced in size or mineralisation noticeably decreases

Frequently Asked Questions