If you were wondering about the real definition of a diamond engagement ring, it may vary with the couples as well as their purpose of gifting the diamond ring. However, promise rings are commonly used as a symbol of commitment that you will get engaged to your partner in the future.
For some couples, it can be an indicator of future engagement. On the contrary, it can be just a symbol of devotion and love towards each other for some couples.
A gold diamond engagement ring is usually gifted to your partner when you feel that she is the one, but you are not ready to get engaged or settle soon. In this case, you must be really attentive while choosing a diamond for your partner.
Note that it is recommended to choose something simple and subtle or something that conveys your exact emotion towards her. Otherwise, your partner may mistake an engagement ring with an official engagement proposal. Moreover, it will hurt her feelings when you clear the misunderstandings later.