EXCEL: What is proper "Type" for Dictionary Key [RESOLVED - Variant!]

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Esteemed Forum Participants and Lurkers:
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Excel 2003, Microsoft Runtime Scripting Library

I can't figure out what the proper "Type" is for Dictionary Keys. The following code runs without Option Explicit, but how do I "Dim" a key variable so that I can turn Explicit back on?

Sub junk()
    'Dictionary requires Microsoft Scripting Runtime in the "Tools > References" List
    Dim aList As Dictionary
    Dim aKey ' As ????????  '<< What is proper Type?
    Set aList = New Scripting.Dictionary
    
    aList.Add "Magic", "Treasure"
    
    For Each aKey In aList.Keys
        Debug.Print aKey, aList.Item(aKey)
    Next
End Sub

Thank you for any and all suggestions, comments, and assistance.