For a future project, I have been sanding and cutting 'Comparta' porphyry. It is very similar to Roman imperial porphyry of antiquity (which for me has been very difficult to locate a safe source of). I was reading some incredible archaelogical notes from http://www.saintpetersbasilica.org/ and am inspired to do a fancy labarum with marble and porphyry. The labarum is the symbol of the Roman emporer Constantine and was common through the late empire.
Porphyry is beautiful and purple, but extremely difficult to work. Notice the pretty white flecks called 'phenocrysts'. I'm worried about how difficult it will be to make discs for an outdoor pavement, since this material eats diamond blades like candy...
A Ruby Ring for a Good Cause
12 hours ago