A number of different trees are referred to as Cedar.
The Eastern Red Cedar is a member of the Juniper family. It's reddish center is very aromatic and is used for lining closets and trunks to keep insects away from heirloom clothing. It is an attractive wood, especially when some contrasting sapwood is included in the turning with the deep red heartwood. However, it is very soft and easily damaged once it has been turned to a final shape. After some time the reddish color tends to soften to a rusty brown.
True cedars are evergreens. Most grow in the Mediterranean region of the world.
Western Red Cedar is in the cypress family. It is a soft wood of a reddish tint. Some red cedar burls are available as pen blanks.
Spanish Cedar is not a true cedar at all, but a deciduous tree that grows in Central and South America.
There is also Alaskan Yellow Cedar and a White Cedar from the American Northeast. These are also rather soft woods. They don't seem to damage as easily as Eastern Red Cedar.
Eastern Red Cedar can be turned for pens. The most interesting coloration comes from where there are knots in the wood. It can fracture along the grain - especially where the grain changes coloring.