Seiko Titanium Automatic Diver SKX405K, Cal. 7S26
Click on the pictures to go through the series

Different Lighting Angle to show Black Gabbro
This difference in lighting shows the structure of the black gabbro nicely. It also creates an interesting reflection of the light bouncing off the crystal. The tripod is in the exactly same position as before, just the panel moved above the watch. I hope you enjoyed the experiment as I did.
Btw. Greg Heath, a fellow TZer from Bangkok pointed out, that this stone is not granite (there are no pink inclusions - feldspar): Here is his original explanation as posted on TZ Public Forum:

The rock is probably an igneous intrusive..

Posted By: Heat <> (
Date: 11/19/01 21:14

mafic rock. You are right in that the rock is not derived from a carbonate and therefore is not marble. I can make out large phenocrysts in a groundmass. To get the large crystals, this rock would have cooled slowly and crystallized deep within the earth. It looks too dark to be a granite. Do you see any pink crystals that a granite would display? probably not.

My guess is that the rock is basic rather than an acidic granite. It is probably a gabbro. Gabbro is composed of plagioclase feldspar with smaller amounts of pyroxene and green olivine. Overall it would have a dark green to black appearance.

Anyway it is nice stuff! Down at the building supplies store it may be referred to as "granite" though.