My RL game tends to be very low optimization and good about Gentlemens Agreement style playing. No one really abuses divinations or scrying, teleportation is usually used as a long distance transportation, things like that. There are times that for story reasons a place should be secure and it's can sometimes be awkward to find reasons (even if only for self consistency) for people/locations to have these specific anti magic measures in place. I'm the back up DM for when out main DM wants to take a bit of a break and I'm looking at running the groups first ever Pathfinder game sometime in the near future and that alone will ramp up the power level a bit. I want to introduce this mostly as a reassurance for the others that there are checks to prevent abuse of that increase in power if needed.

The primary goal in the creation of this object is to provide a non-magical solution that is available to anyone at a relatively reasonable price. Not something your common citizen will have, but easily within reach of successful merchants, nobles and other such figures of significance. I wanted to include counter play measures so that sneaking/socializing your way in to sabotage the device could be a thing. Mostly just looking for feedback on things I may not have thought of with the device itself, holes in the protection or abuse of the abilities etc rather than discussion if it is needed or not. Do you feel the price point keeps it accessible without being too prevalent?

Metalus Null Arcanum

In a modern magical society, the ability to block out certain types of magic is necessary for any expectation of privacy or a secure location. Metalus Null Arcanum, often simply called Null, is the mundane solution which has proven effective in blocking both Scrying and Teleportation magical effects. A Null is an metallic shell created around the core of a Lodestone. The shell is created from a base of Cold Forge Iron woven together with small amounts of Silver and scant amounts of Mithral at key junctions. The metals are not blended in an alloy but rather distinct separate pieces of metal woven together to create a singular whole which uses the different properties of the metal to channel the qualities of the Lodestone into a focused magnetic field which interferes with some magical effects.

A Metalus Null Arcanum is 50 Gold worth of raw materials and a Masterwork component with a value of 50 Gold. The basic Null creates a magnetic field with a 10 foot radius that blocks all scrying and teleportation effects regardless if they are generated by Magic, Psionics or some other effect. Each additional 50 Gold value of raw materials increases this radius by 10 feet to a maximum of 100 feet. The field is blocked by any thickness of metal or more than 1 inch of wood. Scrying effects which create a sensor or locus outside the effect cannot see anything within the area of the field, the protected area is seen as an impenetrable fog or discordant static appearance. Attempting to teleport into the effect will shunt the teleporter to the nearest open space outside the field.

The field created by a Null is slightly unstable and needs to be kept stationary to function reliably. Once placed in a stationary housing or display the field will become increasingly stable over time. After 10 minutes the initial 10 foot radius field is in place and this increases by 10 feet each 10 minutes up to the maximum size the Null is capable of producing. The field can be disrupted by physical contact with a living or undead, sentient being (Intelligence of 3 or better, cannot have the construct type). Each round of direct contact reduces the size of the field by 10 feet. The field will recover at a rate of 10 minutes per 10 feet as if it was newly set up. Moving the Null at least 5 feet disrupts the field in the same way with each 5 feet moved reducing the field by 10 feet which is recovered at 10 minute intervals.

The art of creating the proper channels to focus the magnetic field and render the form into an aesthetically pleasing final form is difficult but very popular with the wealthy elite who seek both the protection of a Null as well as the status of a fine piece of art. Many Nulls are worked into the form of a carving or statue and have great value above and beyond the basic crafting cost. The minimum size is a hollow sphere roughly 6 inches across. A Lodestone is suspended in the center of the sphere and is connected to the shell with woven wires or rods which help focus and channel the field through the guiding circuits of the shell. The default Null has 30 Hit points with a Hardness of 15 and an AC of 12. More elaborate custom Nulls may range in size as determined by the creator and have 30 HP per inch of shell thickness with a Hardness of 15.