Delrin is a trade name for the Polyacetal (POM) family of materials. This is a commonly used material and is well suited for CO2 laser engraving. No color change is achieved with the laser however it does allow for a very high quality engraved look.
Delrin is commonly used for embossing seals such as a Notary Public would use. The file to be engraved can be produced to make both the positive and negative portion of the embossing die. Lasers are ideal for this due to the high precision of the cut.