John (Kiernan) has dragged me out of the woodwork!!
Yes John, there was very little difference between the performance 
and the structure of all the waxes I examined and tested.  The 
studies I did,  did Not include candle wax.  I always presumed it to 
be little different to those we use in histology.  I still believe that to 
be true - although there is probably some addition of a slightly 
harder wax - such as the polishing, or "floor"  waxes.
There was a formulation of histology wax marketed in the USA 
which included a beta terpene (crudely, pine tree "resin").  I found 
that to be particularly helpful in maintaining the interface between 
decalcified  tissue and the solidified wax of the paraffin block. The 
added resin was named "Piccolite" and was produced by an 
American company called "Hercules Chemical Company" if I 
remember correctly.  It did require more careful attention to 
sections on the floating out bath.
When I was able to get hold of the stuff, I used to grind it up in a 
pestle and mortar (what's that?) and add it  at 10% to plain paraffin 
wax.

In structural terms, Paymond A Lamb (A UK company) did 
successfully produce a wax with a significantly different crystal 
structre - VA5 - and which many people  found significantly helpful 
for sectioneing the very hardest tissue.

That of course, is all the theory!  We all know that section cutting 
is an art that is unique to each microtomist and that which works 
best for you IS best!!!........for you!
The important thing is that your supply is "clean" and, especially, 
free of "grit" or any other minute fragments dirt or dust.
Russ Allison, 
Dental School
Cardiff
Wales