This palm sized (after attunement) black crystal ball has no imperfections or visible marks, it is a perfect sphere of jet. When being used to cast a spell the inside billows with clouds colored for the school of magic being used and a fog lifts from it and it turns semi-opaque when being used to scry. 

Notes: Bonus: Spell Save DC, Bonus: Spell Attacks, INERT: Cast Scrying once per long rest the target takes an addition -5 penalty to their saving throw along with normal modifiers. If attuned by an arcane spellcaster (sorcerer, wizard, bard, warlock, arcane trickster, eldritch knight) it acts as a spellcasting focus and gives +1 to spell attack roles and spell save DCs., Focus