Palagonite: high plant-available calcium and silica

Palagonite is a mixture of smectite clays and poorly crystalline feldspars. It is observed as a yellow to orange-brown mineraloid that is optically isotropic and often shows concentric banding. A chemical analysis of Palagonite indicates characteristic high plant-available calcium and silica content and a high cation exchange capacity. It also has high available phosphorus, high conductivity and high micronutrient levels making it a quality soilconditioner. (See analyses on Basalt page)

At Mt Sylvia the basalt lavas flowed into a fresh water lake and reacted with the water partially oxidizing the lavas to form a palagonite rich rock. Some parts of the flow maintain fresh basaltic characteristics. The resource is consequently a mixed product containing both palagonite and blue metal aggregate. Crushing and screening the total product can separate the softer palagonite.

The palagonite is softer than blue metal aggregate and it is easily screened from a crushed product. Organic farmers have commonly used crushed rock as a soil amendment and palagonite is a highly desirable material because it is already oxidized but still retains all plant available elements (no leaching has taken place).

Palagonite can be blended with composted green waste to create a chemically complete fertilizer, retaining all its own chemical benefits as well as the desirable high levels of carbon, organic matter, potassium and calcium that is available from the green waste.