Level
3rd
Casting Time
10 Minutes
Range/Area
1 mile
Components
V, S, M *
Duration
Concentration
10 Minutes
School
Divination
Attack/Save
None
Damage/Effect
Detection (...)
You create an Invisible sensor within range in a location familiar to you (a place you have visited or seen before) or in an obvious location that is unfamiliar to you (such as behind a door, around a corner, or in a grove of trees). The intangible, invulnerable sensor remains in place for the duration.
When you cast the spell, choose seeing or hearing. You can use the chosen sense through the sensor as if you were in its space. As a Bonus Action, you can switch between seeing and hearing.
A creature that sees the sensor (such as a creature benefiting from See Invisibility or Truesight) sees a luminous orb about the size of your fist.
* - (a focus worth 100+ GP, either a jeweled horn for hearing or a glass eye for seeing)
Do you need both a Glass Eye AND a Jeweled Horn to enable both seeing and hearing for Clairvoyance?
If you only have a Glass Eye, does that mean you cannot choose hearing when casting Clairvoyance?
(A literal interpretation of the text is that you only need a Glass Eye OR Jeweled Horn, and either one enables seeing AND hearing with Clairvoyance. I hope that's the intent!)
* - (a focus worth 100+ GP, either a jeweled horn for hearing or a glass eye for seeing)
Approaching this as a developer, I would parse out the condition logic as this:
either (a jeweled horn for seeing) or (a glass eye for seeing)