Alginit, a mineral of natural origin, developed from the mixture of fossil algae-biomass and eroded volcanic tuff 4-5 million years ago. At that time, in the Carpathian Basin, where the Pannonian lake system existed, strong volcanic activities took place. Ring - shaped basaltic tuff craters (called „maar“) emerged from volcanic eruptions.
They played a very important role in the genesis of Alginit. Saline water from the surrounding Pannonian Sea together with fine floating particles penetrated the porous tuff cones. The connection of the outer sea with the inner part of the crater was considerably limited, sometimes restricted, so that neither streams nor waves could disturb the unmoved fluid contents of the crater.
Within the crater of such an erupted volcanic cone a very rare green alga (Botryococcus braunii) proliferated. This alga is a green, pyramid shaped planktonic microalga of the order Chlorococales (class Chlorophyceae). The algae and other floating particles settled down on the bottom of the crater. The resulted mineral is known as Alginit. It developed under anaerobic conditions.
The erosion of the crater rings resulted in an accumulation of macro – and micro nutrients such as P205, Ca, S, Mn, Fe, Cu, K within the crater lake, which supported the multiplication of the algae intensively.
The inflow of hot spring water at 12-14 °C containing carbon dioxide and the resulting constant temperature of the see water provided a positive role for the massive proliferation of the Botryococcus Braunii algae. It is believed that coincidental occurrence of the above-mentioned events resulted in the genesis of the today known Alginit layers.
Alginit belongs to the category of oil shale but it has got unique and individual attributes, which caused an alteration to the basic oil shale in terms of its physical and chemical characteristics. Alginit, with a purity of more than 90%, can only be found in Hungary or more precisely in the Carpathian basin.