Without focus stacking, I doubt you'd get much more in tack sharp focus (you could try going to a higher f-stop, but I wouldn't hold my breath).
All I would be doing differently would be keeping the iso as low as possible, so on a tripod, the base iso would be my setting of choice.
Like the shot, the black background isolates the shell.
You could have just carefully smashed the light bulb that would have got rid of the reflections and with the pumice you need to ground the image its floaty a bit of light spill on the floor would be good, I can't comment on the mineral nature of either Dave I will leave that to the mineral police
with Allan ... especially about the mineral police .. you're safe enough with #2 I should think. very fine detail in the lightbulb but think I like Pumice best for the texture and theme fit ... .which is more than some managed ... oh wait a minute, that's me
My feeling if its not animal or vegetable then it can only be mineral!
Having struggled with pictures of pebbles i can guess how hard the bulb was, congrats!
I don't mind the reflections in the light bulb shot I like the effect on the background. Maybe a different coloured background might have given you more chance for shadows to ground the pumice stone. All these discussions about minerals are making me feel very lacking in the science department - the 52 is nothing if not educational!
I'm pretty sure glass is amorphous solid and as such lacks the lattice structure of a mineral... but tungsten probably is.
Great effort you went through for the light bulb photo.
If in your mind it fits...it fitswell thought out, couple of difficult shots to take.
light bulb ... no matter what the theme, light bulb is truly interesting.
I like the flat look of the pumice stone against the black background with plenty of details in the surface.
brilliant shot of the lightbulb element. not so sure about the pumice.
Nice Dave. Nice black bg and goes well with the lovely black and white shell
Well done on the light bulb, lots of tricky reflections to deal with
Lots of texture in the pumice. Nice.
Hmmmm tough choice Chris, I like the detail of the stone that's for sure, again would like to see some shadow to 'ground it' so my vote goes with the light element, a cool idea that works well for me
Tough choice, I like the bulb and the element for the interesting subject and good detail. Think overall I prefer to stone as it seems to have a bit more visual impact, good detail and stands out nicely against the black background.
light bulb ... no matter what the theme, light bulb is truly interesting.
I'm with d00d on this one ...I really like it.
Mineral - both images fit the theme for me, I do like your lightbulb shot the best.