def __init__(self, rho=RHO_SIL):
        self.cmtype = 'Silicate'
        self.rho    = rho
        self.citation = "Using optical constants for astrosilicate,\nDraine, B. T. 2003, ApJ, 598, 1026\nhttp://adsabs.harvard.edu/abs/2003ApJ...598.1026D"

        D03file = _find_cmfile('callindex.out_sil.D03')
        D03dat  = ascii.read(D03file, header_start=4, data_start=5)

        wavel = D03dat['wave(um)'] * u.micron
        rp  = interp1d(wavel.to(u.cm).value, 1.0 + D03dat['Re(n)-1'])  # wavelength (cm), rp
        ip  = interp1d(wavel.to(u.cm).value, D03dat['Im(n)'])          # wavelength (cm), ip
        self.interps = (rp, ip)