JEWELRY SHOW: Jewelry is a big seller this holiday so far, so for those seeking some unusual pieces, there’s the “Collect Brazilian Jewelry” show featuring Brazilian designers Dorine Botana, Ina Pironi, Glenio DeCastro and Sandra Ceolin, at the Mark Hotel on Madison Avenue and 77th Street, today and Friday. “Each piece is a one of a kind, unique, handmade work of art. The look is organic, natural, colorful and voluminous and everyone know Brazil designs are hot right now,” said show organizer Christine Cachot.