Based on this question I really expected the following to work:
\documentclass{memoir}
\usepackage{amssymb}
\begin{document}
$\mathbb{c,g,d,h,t}$
\end{document}
However, out comes something looking like this:

I have also tried the amsfonts package with the same results. Clearly I have missed something, but what?

stixandxitsfonts. – barbara beeton Nov 14 '13 at 21:43