Identity HelpSmithsonite from Guatemala?
Confused on this specimen. Found in the highlands of Guatemala, Huehuetenango district.
At first I thought it was massive Smithsonite, as it is found locally near some Zinc localities.
But, I think the hardness is off for it. It can NOT be scratched with a fingernail (so not Talc, which I also thought). A steel knife will scratch it, and the mineral itself also scratches glass. I'm not sure what else to use to get the hardness more precise.
It is slightly translucent.
It has a pearly lustre to it and feels slightly velvety.
It does not appear to effervesce in muriatic acid.
It is quite brittle. I broke a smaller piece off a larger piece bare handed.
I tried a Specific Gravity test and got approximately 2.8 - 3
Streak test is bright white.
The first two images are the piece as a whole.
The third image is after I broke it in half to show the inside of it.
Ideas?
This looks like quartz to my eyes. 
" A steel knife will scratch it, and the mineral itself also scratches glass" Can you scratch the glass with your steel knife? If not then I would agree with quartz. Why would the quartz a.) best scratched by a knife and b.) have a pearly velvety lustre? I also question why a knife blade would scratch quartz. Must be some danged good steel. Most knives will not scratch glass which makes me doubt the hardness test. Besides the SG is much too low for smithsonite. 
If a steel knife (mohs 5.5 approx) scratches it but the mineral also scratches glass (mohs 6.5 approx) then your testing is somewhat suspect.
Try again and make sure that you're not confusing a powder trail with a scratch. I'm confused about the hardness test. According to the internet, glass should be about a 5.5 and a knife should be about a 5 to 6.5
Wouldn't that mean the the mineral has a hardness between 5.5 and 6.5? The hardness of a knife varies as does glass. Can you scratch the glass with your knife? no, the knife does not scratch glass.
i'll find a couple bigger specimens on this and see if i can get some better info. Well then your specimen is harder than both the knife and glass. That means it could be quartz.
