Hi Callaway
We would love to see a picture or two!
Is that appraisal for replacement value?
You can search Ebay for similar necklaces- in completed sales -so you know what they actually sold for. That would be pretty close to market value, which is considerably less than replacement value. We do have a member who can tell you market value, but we really need photos.
We have a thread about taking pictures of pearls, but in short, put them on non-refleting white paper like a plain paper towel or a matte napkin. Use the macro setting -the flower- and get as close as possible. The more photos the better we can see your strand. Shoot in indirect light inside and/or outside. Try one shot in the sun. Don't use a flash. A photo with the clasp is helpful. Some clasps are added value.
Besides we just love to see 70 year old akoyas! - that is how old my MiL's akoyas are...which are from the 30s depression era.