Hi Grace,

Thank you for contacting Mearto with your appraisal inquiry.
At any given time in the last few hundred years, there have been dozens if not hundreds of glassmakers working in Murano and the often signed their work (discretely) that can be used to distinguish among makers. An attribution isn't immediately coming to mind so if you find a signature please let me know what it says so I can update this appraisal and possibly reassess its value.
Based on the photos and information provided, and subject to examination, this is:

A vintage Murano hand-blown black and white swirled charger
Made in Murano, Italy, mid 20th Century
Of circular form, glazed in black and white in a complimentary yin/yang pattern; underside bears foil Murano label.
3 1/2 inches high, 16 inches diameter
CONDITION: appears to be in excellent condition
$200-300*
*represents a fair-market value for auction purposes; retail or asking price may vary.

Please let us know if you have additional items to appraise, and thank you again for using Mearto.