Look a little closer
A gold-coloured surface does not establish that an accessory is made from gold. A leather-like texture does not identify the underlying material either. Photographs may reveal a finish while leaving the construction and composition unconfirmed.
A note for your design book
Write visible observations separately from declared material information. For an everyday purchase, consult the actual product information; for a historical object, use its documented record and specialist assessment where needed. Do not perform improvised chemical or destructive tests. This distinction keeps a useful visual description from becoming an unsupported claim about value, authenticity or material content.