1:45 PM - 3:15 PM
[O08-P109] Is hematite the cause of the red color of Makado stone?
Keywords:Makado stone, Aso welded tuff, hematite, Fe2O3, FeO(OH)
Makado stone is Aso welded tuff formed by the eruption of Mt. Aso, and has a unique
pink color. This stone is mainly produced in Amitu Town, Uto City, Kumamoto
Prefecture, and is a stone with a long history. We believe that hematite is
responsible for the pink color of Makado stone, and investigated the following
three points.
(1) Observations and experiments
First, the differences between Makado stone and common Aso welded tuff were
investigated. In addition, we actually generated rust and investigated the
conditions under which it occurs. The results suggest that the color of Makado
stone is due to Fe2O3 or FeOOH, while the black color of Aso tuff is due to
Fe3O4.
(2) Compositional analysis
The compositions of Makado stone and Aso welded tuff were analyzed. Makado stone
and Aso welded tuff were heated in an electric furnace and the changes in color
were observed. As a result, component analysis suggested that Fe2O3 was not the
cause of makado stone color. Furthermore, since both turned red when heated in
an electric furnace, it is thought that the difference in color between Makado
stone and Aso welded tuff is due to iron.
(3) Rock distribution survey and rock identification in Makado area
They actually visited the Makado area, investigated the distribution of rocks, and
made flakes from the rocks they collected and observed them. The results show
that there is no clear boundary between Makado stone and Aso welded tuff, and
it is thought that they were originally the same rock.
conclusion
From (1), (2), and (3), we learned the details of the distribution of Makado stone,
and found that iron is the cause of the color.We also considered that the
Makado stone was originally Aso welded tuff, but was altered by some influence.
pink color. This stone is mainly produced in Amitu Town, Uto City, Kumamoto
Prefecture, and is a stone with a long history. We believe that hematite is
responsible for the pink color of Makado stone, and investigated the following
three points.
(1) Observations and experiments
First, the differences between Makado stone and common Aso welded tuff were
investigated. In addition, we actually generated rust and investigated the
conditions under which it occurs. The results suggest that the color of Makado
stone is due to Fe2O3 or FeOOH, while the black color of Aso tuff is due to
Fe3O4.
(2) Compositional analysis
The compositions of Makado stone and Aso welded tuff were analyzed. Makado stone
and Aso welded tuff were heated in an electric furnace and the changes in color
were observed. As a result, component analysis suggested that Fe2O3 was not the
cause of makado stone color. Furthermore, since both turned red when heated in
an electric furnace, it is thought that the difference in color between Makado
stone and Aso welded tuff is due to iron.
(3) Rock distribution survey and rock identification in Makado area
They actually visited the Makado area, investigated the distribution of rocks, and
made flakes from the rocks they collected and observed them. The results show
that there is no clear boundary between Makado stone and Aso welded tuff, and
it is thought that they were originally the same rock.
conclusion
From (1), (2), and (3), we learned the details of the distribution of Makado stone,
and found that iron is the cause of the color.We also considered that the
Makado stone was originally Aso welded tuff, but was altered by some influence.