"Grrr" is a close up of a stone dog outside a Japanese shrine. I singled it out by saying that most of Brian's photography was of carbon-based objects, except the dog. Joseph doubted that stone wasn't carbon-based. A lively discussion ensued, concluding with me loudly declaring that I had a degree in science and ought to know what was and wasn't carbon-based.
Thus, I present you with several mineral-based examples, taken from Invisible Cities, by Italo Calvino, translated from the Italian by William Weaver, and defined by Oxford Dictionaries Online.
I should now list the wares that can profitably be bought here: agate, onyx, chrysoprase, and other varieties of chalcedony. (12)chrysoprase: an apple-green variety of chalcedony containing nickel, used as a gemstone.
chalcedony: a microcrystalline type of quartz occurring in several different forms, including onyx, agate, and jasper
...everything that moves in the sunlight is driven by the lapping wave enclosed beneath the rock's calcareous sky. (20)calcareous: containing calcium carbonate; chalky.
I climbed the porphyry steps of the palace with the highest domes, I crossed six tiled courtyards with fountains." (47)porphyry: a hard igneous rock containing crystals, usually of feldspar, in a fine-grained, typically reddish groundmass.
This city which cannot be expunged from the mind is like an armature, a honey-comb in whose cells each of us can place the things he wants to remember... (15)armature: a metal framework on which a sculpture is molded with clay or a similar material.