"Microscopic Structure of white Statuary marble." -Geikie, 1893

Marble

"Microscopic Structure of white Statuary marble." -Geikie, 1893

"Microscopic Section of Pitchstone, showing dendritic crystals." -Taylor, 1904

Pitchstone

"Microscopic Section of Pitchstone, showing dendritic crystals." -Taylor, 1904

"Microscopic Section of artificial Porphyrine." -Taylor, 1904

Porphyrine

"Microscopic Section of artificial Porphyrine." -Taylor, 1904