How to draw a 3D aquamarine necklace

How to draw a 3D silver necklace with aquamarine pendant with mixed media on gray paper. 3D illustration by Marcello Barenghi Final picture: Music is royalty-free music from Free Stock Music song link: Materials used: pasteboard (vegetal paper - light gray) 35x25 cm 1,5 mm, typically used for frames, cartonnage and binding), 9B, 7B and B pencils (Caran d’Ache grafwood), paper stomp, Ecoline, colored pencils (Caran d’Ache Supracolor Soft Artis), fibre tip pens (Staedtler Noris Club 320 Double Ended Fibre Tip Pens), markers (Tria Letraset), pens (Pitt artist pen Faber-Castell and Stabilo Felt Tip), black and white acrylic (Decoart and Pebeo), white gel pe