Resonant Amulets and Resonant Spells
Resonant Amulets & Resonant Spells were introduced to Ordo Hermei by Ameline Bonisagi, who discovered the process while attempting to integrate Potent Magic into Hermetic Theory.

A Resonant Amulet is a unique item which may be used as a casting item for a uniquely-designed Resonant Spell.  A Resonant Spell is similar to a Potent Spell, but does not require the Potent Magic Virtue to invent, and the Resonant Spell requires the unique Resonant Amulet as a casting item.

Resonant Amulets  may provide up to twice the usual contribution of a casting item for a Potent Spell compared to the Hermetic Theory Score of the caster.  For example, a Resonant Amulet with a +10 bonus could be learned and cast by a magus with a Hermetic Theory of 5+, rather than requiring a Hermetic Theory Score of 10+. 

Some Resonant Amulets may provide an additional, special aspect to the applicable Resonant Spell.  This special aspect may, if appropriately designed into the spell, enable the spell to function in a manner that differs from standard Hermetic magic, but without violating the Limits of Hermetic Magic. This might be a non-standard Range, Duration, or Target, or some other special benefit.

Obtaining a Resonant Material or Item

In order to create a Resonant Amulet, a maga must first obtain a suitably resonant material or item.  Sometimes, things of virtue may be appropriate, if the thing is unique, and not merely one example of a group of virtuous things.  Some parts of legendary beasts may be suitably resonant, as might be the physical manifestations of Extraordinary Vis.  Ultimately, the only requirement is that the material be unique and special in some way, and is acquired through a challenging story.

Investigating the Properties of a Resonant Material or Item

Once a suitably resonant material or item has been obtained, the magus must determine the innate bonus that will be provided.  In some cases, this may be similar to the material bonus that would be provided by a lesser material.  For example, if the resonant item is a fang from a legendary lycanthrope, a magus might guess that the bonus provided could be similar to that provided by animal bone (+4 to harm or destroy animals).  However, in order to determine the precise nature of the resonant material or item, a magus must spend a season investigating it in a laboratory.  The investigation will succeed if the Intellego Vim lab total of the investigating magus equals or exceeds (5 x innate bonus provided).

Resonant Material Investigation:
Intellego Vim lab total =>  (5 x innate bonus of the resonant material or item)

The magus who investigates the resonant material or item does not have to be the same magus who crafts the Resonant Amulet, or invents the Resonant Spell.  Indeed, a maga might procure the assistance of an Intellego Vim specialist in order to investigate the most potent resonant materials.

Successful investigation could also yield information about a special property of the resonant material or item, if such a property exists.  It is possible that, after a lengthy quest to obtain a resonant material, and time or resources spent investigating the resonant material, a maga discovers that the bonus provided (or the special benefit) is not quite what she was expecting.  However, most magi find some way to make use of such a resonant material or item, given the degree of effort that has gone into obtaining it.

For example, let us suppose that a magus acquires an opal of virtue (RoP:M, 127), which in this case also qualifies as a resonant item.  After investigation, the magus discovers that this particular resonant opal could provide a Resonant bonus for "safe travel +6", and that it also possesses a special property allowing use of a "While traveling" Duration for a Resonant Spell.  This may not have been what the magus was expecting to find, but it would allow him to use a specific version of a  "While (Condition)" Duration for a Resonant Spell, even if he did not possess a relevant Virtue that would give him access to that Duration.

Crafting a Resonant Amulet

Once the resonant material or item has been obtained and investigated, it must be fashioned into a suitable form.  This must be done magically - mundane tools may be used as part of the process, but only a Gifted craftsman can preserve the resonant properties of the material or item through the crafting process.  Magi without a suitable Crafting Ability may use Finesse, with the increase in difficulty that entails.  The most potent Resonant Amulets tend to be crafted by Magi Verditii, who are able to incorporate Verditius Runes into an Amulet, adding to its bonus. 

Only skilled Magi Verditii are able to do this, however, as incorporating Verditius Runes into a Resonant Amulet requires a Philosophiae Score at least equal to the innate bonus the resonant material or item provides.  This is one way in which a Resonant Amulet can provide up to twice the usual contribution: the bonus from the resonant material, and an equal bonus from the incorporation of Verditius Runes.  The contribution from Verditius Runes may not exceed the innate bonus from the resonant material, and if it would be greater, is reduced to an equal value.

The form of the Resonant Amulet may be chosen to provide a suitable shape bonus, if desired.  This is only useful for Resonant Amulets that do not incorporate Verditius Runes.  The bonus from the shape of the Amulet may not exceed the innate bonus of the resonant material; any additional bonus in excess of the innate bonus is ignored.  This is the second way in which a Resonant Amulet can provide up to twice the usual contribution: the bonus from the resonant material, and a shape bonus.  However, unlike the shape bonuses used in enchanting, a symbolic shape worked into the Amulet may not be used.  A shape bonus is only applicable if the resonant material is formed into a significant portion of the shape.  This limitation might encourage magi to research and integrate new shape bonuses into Hermetic Theory, such as through the process of Vulgar Alchemy.

No other material bonuses are applicable to a Resonant Amulet, even if the Amulet includes other materials.  Only the resonant material or item may provide a material bonus.

The bonus provided by a Resonant Amulet is a specific bonus, determined through the combination of the innate bonus provided by the resonant material or item, and a shape bonus if applicable.  Because Verditius Runes are applicable to all Hermetic effects, a Resonant Amulet incorporating Verditius Runes may have more options.  However, the specific bonus of the Resonant Amulet is fixed during the crafting process, and may not be changed thereafter.  Thus, even for a Resonant Amulet with Verditius Runes, the crafter must choose a specific bonus appropriate to the resonant material or item. Once the Resonant Amulet has been crafted, the specific bonus selected is independent of any of the bonuses that combined to form it.

For example, let us take the case of the opal from the example in the previous section.  The magus decides to craft the opal into a charm in the shape of a tiny silver helmet on a silver chain.  This provides a +6 shape bonus to "affect the wearer's sight."  As a result, the charm can provide a potential +12 bonus to the wearer.  Combining the two, the magus can create a specific bonus of +12 for "seeing hazards while traveling."  Also note that although the charm includes silver as a material (+2 Intellego), that material bonus does not apply to the Resonant Amulet, even though one assumes the Resonant Spell would include Intellego in some way.  The magus could have used gold, brass, pewter, or any other suitable material, because it will not affect the bonus for the Resonant Amulet.

Notice that in the example above, the helmet bonus applies to a "wearer," but the Resonant Amulet bonus says nothing about wearing anything.  The merging of the two bonuses yields a new bonus. The bonus from the Resonant Amulet could potentially apply to any sort of Resonant Spell that allows someone to see hazards while traveling, regardless of whether they are wearing a helmet.

Resonant Amulets and Talismans

A Resonant Amulet may be incorporated into a Talisman, if the Resonant Amulet is the most significant component of the Talisman when it is first opened for enchanting. 

For example,  if the Talisman is to take the form of a wooden staff with a gem on one end, and the Resonant Amulet is a semi-precious gem that will be mounted on the end of the staff, that  would meet the requirement : either the gem must be opened, since it has a larger vis capacity than a wooden staff (12 pawns compared to 8), or it will be included if the complete staff is opened for enchantment (gem + staff, 20 pawns).  However, if the same gem were to be mounted on a brass rod (medium base metal, 15 pawns), then the magus would have to open the complete rod (27 pawns total) in order to incorporate the resonant gem, because the other option of opening only the metal rod for enchantment, would not include the resonant gem.

A Talisman that incorporates a Resonant Amulet may include other shape and material bonuses, as usual, so long as the requirement stated above is met.  Bonuses from the other materials may be attuned in the normal manner, but the specific bonus from the Resonant Amulet does not need to be attuned, and the Resonant Amulet itself may not be attuned.  It only applies to the Resonant Spell designed for it, and only provides a bonus for that specific spell.

For example, if the opal necklace from the previous example were incorporated into a talisman, a maga could attune a Talisman bonus for "+2 Intellego" because of the silver in the charm.  However, the opal of the Resonant Amulet could not be attuned for "+4 travel," as it is part of a Resonant Amulet.  The maga could include another (non-resonant) opal into the necklace, and use that opal as a source of attuned bonuses, if she wished.  Similarly, the helmet shape of the Resonant Amulet only applies to the Resonant Amulet.  If the maga wished to attune bonuses related to a helmet, she would need to include a second such charm on the necklace, which could then be attuned to provide appropriate bonuses.

The limitations of incorporating a Resonant Amulet in a Talisman may outweigh the convenience.  Theoretically, multiple Resonant Amulets could be incorporated into a Talisman, if all of the Amulets were included in the Talisman item when it is opened for enchantment.  This would require a high degree of aptitude with Hermetic Theory, and possibly the aid of one or more Mystery Virtues, but it is theoretically possible.

Inventing a Resonant Spell

Once a Resonant Amulet has been created, it may be used as a casting item for a unique Resonant Spell.  Each Resonant Spell requires a matching unique Resonant Amulet, and a Resonant Amulet may only be used for one Resonant Spell.  The two are inextricably linked once the Resonant Spell is complete.  As might be assumed, the bonus provided by the Resonant Amulet must be applicable to the purpose of the Resonant Spell.  A Resonant Amulet that provides a bonus for detecting invisible things will be of no value to a spell intended to ward against fire.

Once invented, the Resonant Spell may be learned, or personally invented from a lab text, by any magus with a Hermetic Theory Score at least equal to one half of the bonus (rounded up) from the Resonant Amulet.  However, only someone with the specific Resonant Amulet for which the spell was designed may cast a Resonant Spell.  Thus, it is possible for several magi to know the same spell, but only one of them could cast it, if he possessed the correct Resonant Amulet.  If none of the magi who know the spell possess the correct Resonant Amulet, then no-one could cast the spell.

Resonant Amulets and Potent Spells

Once a Resonant Spell has been invented, the Resonant Amulet only provides a bonus for that spell.  The essential components of the Resonant Amulet are the resonant material or item, and any shape bonus that was included in the specific bonus of the Resonant Amulet.  Those essential components may not be used as casting items for a Potent Spell - they apply only to the specific Resonant Spell for that Amulet.

Non-essential materials, or secondary shapes, may be used as part of a casting item for other Potent Spells.  For example, the silver in the helmet charm is not an essential material.  If a Potent Spell only requires silver (in any shape) as a casting item, then the helmet charm may be used (or the silver chain in the example could be used).  If the silver must be in the shape of a helmet, then the helmet charm may not be used, because the helmet is an essential component of a Resonant Amulet, and its mystical properties are entirely devoted to that Resonant Amulet.  If the silver must be in some other shape to be used, then the helmet charm would not work, as the silver in it would not be in the appropriate shape.

Using Resonant Spells and Resonant Amulets in a Story

There are several ways in which Resonant Spells and Resonant Amulets can enable interesting and hopefully entertaining stories.  First, there is the story requirement to obtain suitable resonant materials or items.  Characters who want to invent a Resonant Spell will need to obtain the material for the Resonant Amulet.  Even if none of the player characters want to invent such a spell, they may need to locate suitable material as a favor for an NPC, or in return for something they do want.

Second, an existing Resonant Spell and its Resonant Amulet may become the source of a story, if the characters discover a lab text for a very powerful and useful Resonant Spell.  Finding the Resonant Amulet for the spell could become a quest in itself, with all manner of stories emerging as the characters seek clues as to its location.

If the Resonant Amulet had been incorporated into a Talisman at some point in the past, that could provide a potential use for that Talisman, which otherwise would not be of value to any other magus than its creator.

Third, the special properties of some resonant materials or items may provide a story capability that the characters would otherwise lack.