What is the name for nonmetallic minerals that are valued for their beauty and rarity rather than their usefulness?

Answer;

-Gemstones

Gemstones are nonmetallic minerals that are valued for their beauty and rarity rather than their usefulness.

Explanation;

-Most gemstones form in the Earth's crust; the top layer of the Earth, with a depth of 3 to 25 miles. Only two gemstone varieties, diamond and peridot, form in the Earth's mantle, which represents 80% of the Earth's volume.

-A few gemstones form in the mantle, but all gems are mined in the crust. A precious gemstone has beauty, durability, and rarity, whereas a semiprecious gemstone has only one or two of these qualities.

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).