There is a Pinus Parviflora (dark round) or Pinus Ponderosa (with a 'tail') seed in your hands.
And here it is, a 'recipe' to plant it:
Firstly you have to stratify the seeds: Mix them with moist peat or sand, place them in a clear plastic bag, and refrigerate them for three to seven weeks. (If the seeds germinate in the refrigerator, sow them immediately. Normally they will do it in the soil) Sow the seeds in 3-inch pots, and provide bottom heat of about 60'F (15'C). Seedlings can be transplanted outdoors into larger pots, when they’re about 2 inches tall (six to eight weeks after they germinate).
And this is it! Enjoy your new tree ♡