I'm describing the properties of a molecule, and I'm wondering if it's correct to say this -

Physical properties: Fine, white, crystalline, powder

OR should I remove the commas and write -

Physical properties: Fine white crystalline powder

You should keep the commas if you can do the following:

~ insert "and" between the adjectives
or
~ put those adjectives in different order and they still make sense.

If you cannot do either of those things, then you need to keep the commas.

Use commas

Both versions are correct, but the choice between using commas or not depends on your writing style and personal preference.

If you choose to use commas, the phrase would be written as: "Physical properties: Fine, white, crystalline, powder." This format separates each adjective with a comma, emphasizing each individual property.

However, if you prefer not to use commas, the phrase would be written as: "Physical properties: Fine white crystalline powder." This format omits the commas and creates a more streamlined description.

Both versions effectively convey the same information. The decision of whether to use commas or not is simply a matter of writing style.