Fulgurites, "fused lightning", natural glass curiosities

These are rather interesting pieces - fulgurites, or specimens of "fused lightning" from Algeria, North Africa, probably the Sahara Desert.

When lightning strikes sand, such as on a beach or in the desert, the immense energy goes into the ground, fusing the silica in the sand along its path into sand-encrusted rudimentary glass, often as thin walled tubes. These are small examples and are mounted vertically on posts.  You can clearly see that they are delicate hollow tubes.

Fulgurites are known to occur up to 49' (15 m) long/deep and nearly 8" (20 cm) across, so these ones really are tiny!  I can see them working in both 1:12 and 1:24 scale settings.

Left:  13/16 inch (2.0 cm) tall.

Centre:  Just under 3/4 inches (1.9 cm) tall.

Right:  Just under 1/2 inch (1.3 cm) tall.