Please see above for visual representation of hollow vs. solid. In jewelry there's either hollow or solid, there's no such thing as semi-hollow or semi-solid and such words are mostly used as dirty marketing tactics by some jewelry retailers to persuade buyers into their "trap".
In layman's terms, the main difference between solid and hollow gold link jewelry lies in the way they are made and their overall weight.
Solid gold link jewelry, as the name suggests, is made entirely of gold throughout its construction. It is crafted by shaping and joining individual gold links, creating a chain or bracelet that is solid and substantial in weight. Solid gold jewelry tends to be more durable and resistant to wear and tear since it is made entirely of gold.
On the other hand, hollow gold link jewelry is crafted by creating a thin outer layer of gold that encases a hollow interior. This means that the inside of the links is empty, resulting in a lighter piece of jewelry compared to its solid counterpart. Hollow jewelry is typically made by using a process called electroforming, where a base material is coated with a layer of gold. While hollow gold jewelry can be more affordable and have a similar appearance to solid gold, it is generally less durable and may be more prone to denting or damage.
In summary, solid gold link jewelry is made entirely of gold and tends to be heavier and more durable, while hollow gold link jewelry has a hollow interior, making it lighter but potentially less durable. Both types can be visually appealing, but it's important to consider your preferences, budget, and desired level of durability when choosing between them.