We present Lick spectral indices for a complete sample of 139 candidate super metal-rich stars of different luminosity class ( MK type from V to I ) .
For 91 of these stars we were able to identify , in an accompanying paper ( Malagnini et al . 2000 ) , the fundamental atmosphere parameters .
This confirms that at least 2/3 of the sample consists of stars with [ Fe/H ] in excess of +0.1 dex .

Optical indices for both observations and fiducial synthetic spectra have been calibrated to the Lick system according to Worthey et al . ( 1994 ) , and include the Fe i indices of Fe5015 , Fe5270 , and Fe5335 , and the Mg i and MgH indices of Mg _ { 2 } and Mgb at 5180 Å .

Internal accuracy of the observations is found to be \sigma { ( Fe 5015 ) } = \pm 0.32 Å , \sigma { ( Fe 5270 ) } = \pm 0.19 Å , \sigma { ( Fe 5335 ) } = \pm 0.22 Å , \sigma ( Mg _ { 2 } ) = \pm 0.004 mag , and \sigma ( Mgb ) = \pm 0.19 Å .
This is about a factor of two better than the corresponding theoretical indices from the synthetic spectra , the latter as a consequence of the intrinsic limitations in the input physics , as discussed in Chavez et al . ( 1997 ) .

By comparing models and observations , no evidence is found for non-standard Mg vs. Fe relative abundance , so that [ Mg/Fe ] = 0 , on the average , for our sample .

Both the Worthey et al . ( 1994 ) and Buzzoni et al . ( 1992 , 1994 ) fitting functions are found to suitably match the data , and can therefore confidently be extended for population synthesis application also to super-solar metallicity regimes .
A somewhat different behaviour of the two fitting sets appears , however , beyond the temperature constraints of our stellar sample .
Its impact on the theoretical output is discussed , as far as the integrated Mg _ { 2 } index is derived from synthesis models of stellar aggregates .

A two-index plot , like Mg _ { 2 } vs. Fe5270 , is found to provide a simple and powerful tool to probe distinctive properties of single stars and stellar aggregates as a whole .
The major advantage , over a classical c-m diagram , is to be both reddening free and distance independent .