Ore veins can often be found in the mines around Cyrodiil. There are two main types: Silver Veins and Gold Veins. The Mehrunes' Razor official download adds Iron Veins, and the Vile Lair download adds Purgeblood Crystal Formations. Ore veins are treated like containers, meaning you can store items in them (although not always safely). Pickaxes can be found as random clutter, but they are not needed to interact with veins.
Silver Veins have a chance of containing up to three Silver Nuggets. There are a total of ninety veins, which come in three varieties. None of them respawn, meaning that Silver Veins are safe to use as storage containers. Gutted Mine contains the highest amount of veins: eight.
Gold Veins have a chance of containing a single Gold Nugget. There are only eight veins in total, which come in three varieties. They are located in Abandoned Mine and Desolate Mine. None of them respawn, meaning that Gold Veins are safe to use as storage containers.
Iron Veins are added by the Mehrunes' Razor official download. They can contain one or two pieces of Iron Ore. There are fifteen veins, which come in three varieties, all located within Sundercliff Watch. They respawn, meaning that they are not safe for storage but provide you with an infinite amount of Iron Ore.
Purgeblood Crystal Formation
Purgeblood Crystal Formations are added by the Vile Lair official download. They contain a sample of Purgeblood Salts. Only three exist, having been created by Greywyn in Deepscorn Hollow. The veins come in three varieties. They respawn, meaning that they are not safe for storage but provide you with an infinite amount of Purgeblood Salts. A bug with the veins allows you to quickly obtain limitless amounts of Purgeblood Salts.