Silvery Oil Spot Glaze

These two glazes are mirror bright glossy, though retaining the brushed metallic texture seen in these glazes.

The high silica/high alkali metal glaze mashiko_ZS_2 is heavily dimpled with large oil spots. It is seen to have high viscosity,
and likely high surface tension. Large pinholes which don't heal shows the low fluidity of this glaze.

The high Calcia glaze mashiko_ZJ_2_N is less viscous and more fluid. This is seen in the smaller less dimpled oil spots.

It is interesting that what appears to be a similar surface texture - a brushed metallic high gloss surface
occurs with such differing compositions.

glaze composition

Emperical Formula mashiko_ZS_2

K2O        0.14
Na2O        0.14
Li2O        0.12
CaO        0.21
MgO        0.39

Al2O3        .82
Fe2O3        .22

SiO2        6.1

molecular percent Silica 75 %

Emperical Formula mashiko_ZJ_2_N

K2O        0.09
Na2O        0.1
Li2O        0.09
CaO        0.31
MgO        0.41

Al2O3        .82
Fe2O3        .23

SiO2        5.7

molecular percent Silica 74 %

The bowls are ~ 5 inches in diameter.

The glaze is shown on the inside and outside, resp left and right.

The gold/brown markings in the bowl with mashiko_ZS_2 are an inlaid second glaze decoration created by applying a glaze over a mask,
waxing, removing the mask and filling in the second decorative glaze.

The glaze is thinner on the outside of the bowl with glaze mashiko_ZJ_2_N, that is not the cause of the color change.
mashiko_ZJ_2_N is translucent, the glazes in this family are brown with a surface layer of silvery crystals. The differing angle
of the light on the transparent glaze exposes the underlying brown layer.

Glaze mashiko_ZS_2

Glaze mashiko_ZJ_2_N