The FT-Raman spectra of an Antarctic endolith from the LTER site at Lake Hoare are reported. The specimen provides an unusual occurrence of endolithic colonization of an igneous rock substratum, which analyses as microcline feldspar. The presence of aragonite in the red biological stratum and calcite in a fissure of the rock which has not been subjected to colonization can be attributed to the penetration of calcareous deposits from shallow ground water in an earlier environment in the Dry Valleys. The green biological layer is composed of chlorophyll and β-carotene. Comparison with previous Raman spectroscopic work on endoliths in sedimentary Beacon sandstone is effected.