Natural Zeolite Pozzolan Comparison
A comparative study comparing clinoptilolite zeolite with silica fume, fly ash and a non-zeolitic natural pozzolan

A recent study published this comparison of clinoptilolite zeolite against silica fume, fly ash, and a non-zeolitic natural pozzolan. The results are very interesting. 

Clinoptilolite is the most common of natural zeolites. In this study researchers compared this mineral as a natural pozzolan, versus other pozzolanic options, in lime pastes. The results showed that the clinoptilolite possesses a high lime–pozzolan reactivity that is comparable to silica fume and is higher than fly ash and the non-zeolitic natural pozzolan.

In the first few minutes of contact with lime, the pozzolanic activity of the zeolite was comparable to the silica fume, but was higher than the fly ash and the non-zeolitic natural pozzolan. 

The zeolite consumed much more Ca(OH)2 when compared to fly ash and the non-zeolitic pozzolan.

Full research paper:

Ancient Zeolite Water Purification System Discovered
Natural Zeolite Water Purification found in Ancient Mayan Civilization of Tikal