Spanish Main

G'day,
when you say "engraving", I wonder if you are referring to "chopmarks", which are often Chinese characters. I haven't seen a lot of them, but they've all been struck, as with a hammer striking a die.
Chopmarks are common on silver coins: Spanish dollars certainly; British Crowns occasionally. I don't collect American dollars, so I haven't noticed any.
Peter

There are many, many coins that made it to China, and were chopped with the Chinese chopmarks. To them, chopmarks were their version of coin grading! Many unscrupulous coin traders would use counterfeit or base metal coins, instead of the silver rounds the Chinese wanted. Each individual merchant had a process by which he would grade the silver content in each coin. When he was satisfied that the coin stood up to his standards, he would stamp it with his 'signature', the Chinese characters we call Chopmarks today.

There are two types of Chopmarks. Type 1 marks are small and do less damage to the surface of a coin. Type 2 marks are large, and can often cover the surface of a coin until the coin literally falls to pieces!

Any coin which circulated in China can have chopmarks on it. Silver, gold, or copper coins were traded, though the large trade silver coins were by far most prevalent. Many countries issued silver Trade dollars, expressly for the purpose of shipping to trade in China. The US Trade dollar, so unpopular here at home, is one good example.

The Spanish 8 Reales, and after Mexico declared independence the Mexico 8 Reales Cap & Rays coins were preferred by the Chinese merchants.