Alright, i liked the meaning of this one but i have several suggestions. Mainly, try and eliminate unnecessary words, it sounds and reads better without them (just my style and opinion). you also say the necklace is beneath the sea and lake? kinda confusing, pick one.

line3- this one can go either way its personal preference but consider removing 'it is'
line 6- "there are memories no left blank": not sure what you were trying to say. I think no = now but that still doesn't help me understand it so i don't know.
lines 9/10-you start with "the one's that's helped me": "one's" is possessive but i think you meant it to be plural instead. the thing is, one is a singular word, despite common speech patterns i don't believe there is actually a plural. try "memories" instead. if you did mean the word to be plural as i thought, then "that's" needs to be changed to "that have". if you meant it to be singular then eliminate the " 's" from "that's". I think this poem needs a little touching up but has the potential to be really great. These are just my suggestions, i could be wrong about most of them.