Question: I see that, for example:

> 
> A cleric or paladin can use a holy symbol as a spellcasting focus, as described in chapter 10. To use the symbol in this way, the caster must hold it in hand, **wear it visibly,** or bear it on a shield.
> 
> 
> 

Further, I see that the standard arcane focuses -- orbs, crystals, rods, etc. -- all have to be held in the hand. That makes sense to me.

What I'm *not* sure about is, for example, the *Hat of Wizardry* or the *Dark Shard Amulet* from XGTE. Both specify they can be used as a spellcasting focus (for wizards and warlocks respectively), but it does not make sense to me that e.g. a wizard would be required to hold their *Hat of Wizardry* in their hand to use it as a spellcasting focus, instead of wearing it. I can imagine a warlock having to grip their *Dark Shard Amulet* with a free hand, but that still seems like a bit of a stretch, especially when combined with somatic components.

Can these specific foci be used without holding them in hand?

Answer: 
They don't need to be held in the hand to be used as a focus.

The magical items Hat of Wizardry and Dark Shard Amulet are templated differently than the nonmagical Holy Symbol because of the additional ability they have. Instead of a single statement, they use a bulleted list. The list could be expanded into statements to match the templating on Holy Symbol:

> 
> A wizard can use a Hat of Wizardry as a spellcasting focus for wizard spells. To use the hat in this way, the caster must wear it visibly.
> 
> 
> While you are wearing the hat you can try to cast a cantrip that you
> don't know. The cantrip must be on the Wizard spell list, and you must
> make a DC 10 Intelligence (Arcana) check. If the check succeeds, you
> cast the spell. If the check fails, so does the spell, and the action
> used to cast the spell is wasted. In either case, you can't use this
> property again until you finish a long rest.
> 
> 
> 

And we could change the Holy Symbol templating to be worded with the (single item) bulleted list of effects:

> 
> A holy symbol is a representation of a god or pantheon. While holding the symbol, wearing it visibly or wielding a shield with the symbol emblazoned upon it you gain the following benefits:
> 
> 
> * You may use the symbol as a spellcasting focus for your cleric or paladin spells.
> 
> 
> 

These are both awkward - the first combines multiple abilities into blocks of text and references the wearing condition twice, the second has a list with only one item in it. These are simply two ways of saying the same thing, written differently based on the other circumstances of the item.
**Yes**, the *Hat of Wizardry* and the *Dark Shard Amulet* must be held in hand to be used as focus.

The rule for material components is found in the Player Handbook's errata:

> 
> **Material (M)** A spellcaster must have a hand free to access a spell’s material components—or to hold a spellcasting focus — but it can be the same hand that he or she uses to perform somatic components.
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This makes it clear that a free hand is required to hold the spellcasting focus.

For the Holy Symbol, its description (p. 151) specifically states that it can be used as a spellcasting focus under broader conditions than normally allowed by the rules:

> 
> **Holy Symbol**. A cleric or paladin can use a holy symbol as a spellcasting focus, as described in chapter 10. To use the symbol in this way, the caster must hold it in hand, wear it visibly, or bear it on a shield.
> 
> 
> 

However, there is no such mention in the description of the *Hat of Wizardry* and the *Dark Shard Amulet*. The text only states that they can be used a a focus:

> 
> **Hat of Wizardry**. You can use the hat as a spellcasting focus for your wizard spells.
> 
> 
> **Dark Shard Amulet**. You can use the amulet as a spellcasting focus for your warlock spells.
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This is not different than the description for other foci, such as the Arcane Focus:

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> **Arcane Focus**. A sorcerer, warlock, or w izard can use such an item as a spellcasting focus, as described in chapter 10.
> 
> 
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The only difference is that the hat and amulet have the additional requirement that they be worn before they can be used a focus.