Gold, silver and sterling silver can be engraved by hand or by machine, cannot be engraved by a laser.
Can we hold it?
This will be the first question of the engraver when looking at a consumer's piece: if it can't fit in the holder, then it can't be engraved. Different machines allow for the engraving of differently shaped objects. Most objects can be engraved, one way or another.
Contrary to the common belief that hand engraving is done completely by hand, it requires a basic, simple machine that holds the item being engraved and guides the engraver through the fonts using strong and sturdy metal guides. Experts at hand engraving will built their own custom guides over years and years of satisfying customer needs.
Pros and Cons: These archaic looking machines allow for imperfections. As the engraver applies pressure (unevenly) on his machine and spaces the letters and words approximately, the quality of the engraving varies with the experience, talent and sometimes fatique of the master. This is a labor intensive tool and its outcome is often flawed by human errors and mistakes (although not always visible to the unaware eye). This is a preferred tool of engraving for companies that look to charge more to its customers since it is more labor intensive. It is also recommended when machine engraving is difficult because of the shape of the object (most engraving machines can only hold flat objects. But it gives a feel of antiquity and authentic engraving. Some say that it allows for deeper engraving and that it will last longer, but that is legend since engraving machines are more powerful and often apply more pressure and do so more evenly than humans.
This is the prefered tool for flat pieces and logos (no hand engraver will built a logo guide for just one piece!). Most engraving machines are limited to engraving flat pieces. Recent to the market are a few new machines which compete with hand engraving in that it offers a better quality of engraving and is less labor intensive, therefore less expensive and more even than hand engraving. However, most engraving machines do not handle circular or uneven objects.