Jadeite and nephrite are different mineral materials both called jade. Myanmar's Hpakant area is an important jadeite-producing region. A geographic label on a listing is not item-specific proof of origin.
Trade descriptions such as "Mandalay jade" do not establish geological origin, treatment or a chain of custody. For an individual piece, request supporting records and independent gemological assessment where available.
Collecting jadeite calls for careful review of treatment, color, translucency, texture and documentation. Future resale value cannot be guaranteed. Ask an independent laboratory to assess individual stones.
Old mine is a trade term used in different ways. Do not infer a deposit, mining date or price premium solely from that label. Compare the item itself and any documentation before deciding.