Several fine lines appeared on the surface of LiNbO3 single crystals grown perpendicularly to the (112) plane from the melt. They ran approximately parallel to the pulling axis from the middle of the cylindrical wall to the tail without terminating in the boules. X-ray analysis showed them to be a lineage structure with a large rotation of the crystallographic axis around the pulling axis and with small tilted orientations perpendicular to the pulling axis. The structure initiates on the lateral surface during crystal growth and is dependent on the growth direction and the crystal diameter. It is stable the finding that the structure does not reform when annealed at 1150degreesC. Transfiguration of growth ridges by the lineage structure and the solid-liquid interface is flat imply that the lineage structure occurs during crystal growth. The structure forms from nuclei occur on the lateral surface of the crystals and they can develop under crystal growth conditions that produce a convex solid/liquid interface towards the liquid. The nuclei result from changes in the surface in response to surface stress. (C) 2005 Springer Science + Business Media, Inc.