Enchanted Glyphstone

A slick dark stone, obsidian-like around 6" long and 2.5" wide, and around 1/4 inch high. One side has a single glyph etched into the stone, the other side seems to have many minute runes running down the face of it, too small to really see or fathom how it was etched, none of the runes are too deep so the stone feels almost completely smooth and the runes are only noticed when examined closely and one has the light play off the face. When held it emanates a faint magical white aura, pulsing ever so softly with energy.

Requires Attunement by a spellcaster of any kind, but it is a special attunement. Once the hour has been spent to attune you can choose 1 other item to attune to, now you can switch between these attunements with a 5 minute ritual. If you want to change out the other item it will require a full hour attunement again.

Powers

Must be held to use these spells.

Light:

It can Light up at will, glowing with 5" bright Light, 5" soft Light. A bonus action to turn on or off.

Replace Sending Stone:

If one has a Sending Stone they can "attune" the enchanted glyphstone to replace that stone making the old stone "disappear" into it. Once this is done a magic word is created by the caster attuned to this. That word is not discovered by an Identify spell, so it is always possible a found enchanted glyphstone is synced with other stones out there. There is no limit to number of such stones it can sync to. One note on this -- the glyphstone can be found by the person who holds the paired Sending Stone if they are aware of the sync, unless the paired Sending Stone is also absorbed into a glyphstone -- in which case neither stone can find the other. If a person knows the Sending Stone is synced to a glyphstone it will glow when it is within 5 miles of the glyphstone and that color shifts to red as it gets closer to the glyphstone.
This is one reason why some worry about such pairing as it can be a bit of a security concern.
With this glyphstone you can cast Message as the spell, item must be held though.
Cast Sending as the spell, costs 1 charge. 2 charges if they are on a different plane (whether or not it connects).
Cast Identify as the spell, costs 1 charge.
Cast Legend Lore as the spell, costs 4 charges
Doesn't grant you Scrying, but can be used as the 1,000 gp focus for the Scrying spell, and grants a -1 save modifier (negative is good in this case, per the spell description).

Charges:

The Enchanted Glyphstone regains 1d4 expended charges daily at Dawn. It can hold a maximum of 6 charges.

Charging:

The device can be recharged using magical energy (spell slots). Each spell slot expended restores 1 charge.

Spellcasting Focus:

The Enchanted Glyphstone can also function as a spellcasting focus for the attuned user.
This is unique item only found on Eberron, and only a few were ever made before their method of Creation was lost to time. They are prized by those who are lucky to come across them.

Legendary wonderous item requires attunement by spellcaster, but a special attunement
Replace Sending Stone, stipulations.
Cast Light, at will
Cast Message, at will
Cast Sending, cost 1 charge (2 charges if they are on a different plane)
Cast Identify, costs 1 charge
Cast Legend Lore, costs 4 charges
Can be used as a focus for a Scrying spell and grant -1 modifier to the target's save.
Charges: The Enchanted Glyphstone regains 1d4 expended charges daily at Dawn. It can hold a maximum of 6 charges.
Charging: The device can be recharged using magical energy (spell slots). Each spell slot expended restores 1 charge.
Spellcasting Focus: The Enchanted Glyphstone can also function as a spellcasting focus for the attuned user, as long as it is the current attunement (in regards to its special attunement property)