Is an altar that is used in the casting of sigils. This will be the place in witch you will charge, and activate alot of your sigils. This will be a place to keep sigil journals, notes on your alphabet of desire, linking sigils, sigil matrices, and many other things relating to your sigil practice. On your sigil altar you also keep linking sigils, and sigil matrices allowing you to send specific energies to specific places from this location.  You will also be able to keep the sigils of your servitors, and any other thought forms here also to be connected to your network into work for you. This place will live, and breathe your sigil practice, and will contain the energies, tools, and knowledge in order to create, and use sigils. These places will definitely be very personal for the practitioner that owns them, and will most likely be set up in a way that they find fit, so no to alters will probably look the same. Not all sigil practitioners will have sigil Alters, but it may be a good thing to have if you are one.