Thank you for submitting your item for appraisal. This appears to be Mancos Black-on-White Anasazi earthenware seed jar, decorated with volutes and parallel lines. The material, execution and surface patina perfectly fit to the provenance you stated. While this is a family heirloom to you, there is also a current market value. The estimate is based on similar items sold at auction recently. There is no measurement for the sentimental value you might attach to the item. "Asking prices" in the trade can be higher and vary.