Prismarine Shards are items added in 14w25a that can be obtained by defeating the Guardian mob. They can be crafted into Prismarine variants such as Prismarine Brick and Dark Prismarine.
After veg they will usually flower for anywhere for 8 to 9 weeks. The breeder recommends growing Jack Berry F2 in a SCRoG type grow, where the yield can reach above average, at best. This is a strain that spends most of its energy developing trichomes, rather than bud mass. Don't expect huge yields with this one. In most cases, it simply isn't possible.
The F2 generation from that cross is then analyzed. The results of this analysis can be used to find which genotypes correlate with specific bone properties like size, density, and failure load. The anticipated outcome of this lab is the identification of the genotypes that affect bone strength in mice.