\begin{table}%T2
\par
\caption{\label{table:1}Experimental samples: manufacturer information and references.}
\small%\centerline
{
\begin{tabular}{lcccccc}      
\hline\hline
Polytype & Mineral Name & Grain Size
& Manufacturer & Refractive Index & Comments \\
 \hline 
 $\alpha$-SiC & synthetic & diam. = 6.5~mm
           & Charles \& & $n_{\rm o}$~$=$~2.654$^a$
          & round brilliant \\
 & moissanite & & Colvard, Ltd$^{\rm TM}$ & $n_{\rm e}$~$=$~2.967 & cut gem \\
 $\alpha$-SiC & 6H-SiC & 2~$\mu$m powder; & Alfa/Aesar & $n_{\rm o}$~$=$~2.55, $n_{\rm e}$~$=$~2.59 (IR)
    & hexagonal plates \\
         & (gray, amber) & surf. area $=$~9--11~m$^{2}$~g$^{-1}$
            & (Lot \# C19H06) & $n_{\rm o}$~=~$2.5531+(3.34\times 10^{4})\cdot \lambda^{-2}$, & purity: 99.8\% \\
              & & & & $n_{\rm e}$~=~$2.5852+(3.68\times 10^{4})\cdot 
	\lambda^{-2}$$^b$ & metals basis \\
   $\alpha$-SiC & 6H-SiC (blue-gray); & several mm & unknown & $n_{\rm o}$~$=$~2.654$^{{a}}$ & Hopper crystal; \\
         & synthetic & per crystal & & $n_{\rm e}$~$=$~2.967 & (i.e., intergrown \\
	 & carborundum & & & & crystals) \\
   $\alpha$-SiC & 6H-SiC (green, & 4$-$8~mm wide, & Morion Co. & $n_{\rm o}$~$=$~2.654$^{{a}}$ & green: layered, hexagonal, flat \\
         & yellow) & 0.25$-$1.20~Car. each & & $n_{\rm e}$~$=$~2.967 & yellow: single crystal\\
   $\beta$-SiC & 3C-SiC wafer & diam~$=$~5~$\mu$m & Rohm \& Haas,
        & $n_{\rm o, e}$~$=$~2.55$^{{b}}$ & CVD wafer \\
        & (fcc cubic) & & Advanced Materials & $n_{\rm o, e}$~=~$2.55378+(3.417\times 10^{4})\cdot \lambda^{-2}$~$^{{c}}$ & purity: $\geq$99.9995\% \\
        & & & (Grade SC-001) & \\
   $\beta$-SiC & 3C-SiC gray & diam. $\sim$2.5$-$25~$\mu$m  & Superior Graphite 
       & $n_{\rm o, e}$~$=$~2.55$^{{\rm b}}$ & equant (spherical) \\
        & (fcc cubic) & & & $n_{\rm o, e}$~=~$2.55378+(3.417\times 10^{4})\cdot \lambda^{-2}$~$^{{c}}$ & chips \\
 \noalign{\smallskip}\hline
 \end{tabular}}
 \smallskip
 $^a$  Indices of refraction for
	   the O-ray ($n_{\rm o}$) and E-ray ($n_{\rm e}$) given for
	   white light (Gaines et~al. \cite{Gaines1997}) or IR $\lambda$ (Goldberg et~al. \cite{Goldberg2001}). \\
	   $^b$  Values for visible light (467~nm~$<$~$\lambda$~$<$~691~nm at $T$~$=$~300~K; Schaffer \& Naum \cite{Schaffer1969}; 
	Schaffer \cite{Schaffer1971}).
	Formulae assume $\lambda$ in nanometers. 
 \end{table}