1/6 precious gems.
1. Make 1/3 into a fraction with the denominator as a 6. Then multiply the top number to have faction of 2/6
2. Do the same to 1/2, except multiply the top number by 3 because 2x3 is 6
3. Add the two new fractions together to get 5/6.
4. Now subtract 5/6 form 6/6 to get 1/6. The precious gem necklaces.