Cashews would be the closest in texture and depth of flavor.
Walgreens Drug Store carries macadamias in the nut/snack section.
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My family owns 10-1/2 acres of macadamia nut trees on the big island of Hawaii, just up-slope from Hilo. Whoever goes next, has to bring back a duffle bag of husked, but unshelled nuts. The grandkids then sit on the deck with a cinderblock and hammer, and shell them. Of course we only see a portion of them at first because the kids do a "One for me and one for you..." But that only lasts for a while. Macadamias, in large quantities, have a laxative effect! LOL!