Samples with 10Nd(2)O(3). 5CaO . 17Al(2)O(3). 68SiO(2) composition (mol %) were prepared by the sol-gel method and by melting. The structure of the samples was investigated by X-ray diffraction, scanning electron microscopy, infrared spectroscopy, a.c. susceptibility measurements and electron spin resonance. The gel-derived sample heat-treated between 250 and 700 degreesC is amorphous and has a granular microstructure. In the samples heat-treated at 800, 900 and 1000 degreesC we detected by X-ray diffraction AlNdO3 crystalline particles. The melted sample was amorphous and the micrograph shows a glass matrix containing particles. The infrared measurements show structural changes produced by the heat-treatment of the gel samples. The magnetic susceptibility data indicates that neodymium oxide is present in these samples as Nd3+-O-Nd3+ aggregates with an antiferromagnetic interaction.