Using a black square as list icon: How to position it correctly?

Question

I would like to use a black square ■ instead of the standard bullet • for lists. Now its default size is a bit too big for my taste, so I shrank it down and ended up with the following definition (MWE below):

\renewcommand\labelitemi{{\tiny $■$}}

Unfortunately, this will make the baselines of the square and the following list item align, i.e. the square will not be centered vertically with respect to the following text. How do I fix this? Any help would be much appreciated!

MWE:

\documentclass[12pt,a4paper]{memoir}

\usepackage{fontspec}
\usepackage{xunicode}
\usepackage{mathtools}
\usepackage{unicode-math}

\usepackage{enumerate}
\renewcommand\labelitemi{\tiny $■$}


\begin{document}

Some sample text

\begin{itemize}
  \item Foo
  \item Bar
\end{itemize}

\end{document}

Answer 1

Like this:

With use of the enumitem package and defined square by \rule:

\documentclass[12pt,a4paper]{memoir}

\usepackage{fontspec}
\usepackage{xunicode}
\usepackage{mathtools}
\usepackage{unicode-math}

\usepackage{enumitem}
\setlist[itemize]{label=\rule[0.5ex]{0.6ex}{0.6ex}}


\begin{document}

Some sample text

\begin{itemize}
  \item Foo
  \item Bar
\end{itemize}

\end{document}

Answer 2

I adopted an another strategy using into \labelitemi, the option \raisebox{.25\height} where it is possible to move up or down the position of the little \blacksquare symbol. The choice of the position depends of the value of .25: if this number is positive the blacksquare will go upwards. If this number is negative it will go downwards. Here there is a MWE with the screenshot.

\documentclass[12pt,a4paper]{memoir}
\usepackage{amssymb}
\usepackage{fontspec}
\usepackage{xunicode}
\usepackage{mathtools}
\usepackage{unicode-math}
\usepackage{enumerate}
\renewcommand{\labelitemi}{\raisebox{.25\height}{\tiny$\blacksquare$}}
\usepackage{lipsum}
\begin{document}

\noindent \lipsum[1][2-3]

\begin{itemize}
  \item \lipsum[1][3-4]
  \item \lipsum[1][5-6]
\end{itemize}

\end{document}