Veins

Veins, added by Deadly World, are variations on the Gravel and Dirt veins from Vanilla Minecraft. Veins for anything from Water to Lava to Sand to Silverfish blocks can generate in veins. The rarity and size of all the veins can be changed in the config file.
 * Water Veins can generate anywhere below layer 62 that is not exposed to a cave or the surface. These veins generate 3-5 water source blocks, and are as rare as gold.
 * Lava Veins can generate below layer 32, and are almost exactly like Water veins. These veins are twice as common as gold.Veinlava.jpg
 * Sand Veins can generate anywhere below layer 62 and are very large. However, the sand veins are rarer than diamonds, but tend to make their presence known, due to extreme size. The sand veins are generated after basic world gen, and will not replace anything but stone, meaning ores or gravel could be enveloped by the large vein.Veinsand.png
 * Silverfish Veins replace can replace any stone blocks with Silverfish eggs. These veins can spawn anywhere below layer 128 and are half as common as coal veins. They are somewhere between a dirt vein and a coal vein in size.