A closer look
Pale colour, particles and pores can be photographed. They do not establish ingredients, binders or proportions. Avoid scratching, wetting or soaking as improvised tests; preserving a fragile surface comes first.
How to continue
Continue looking: write down visible details and keep interpretations in a separate column. Record viewing conditions, the photograph date and missing information. Revise when evidence changes, so the next reader can see what supported each judgement.
Scope: this is an editorial close reading. References support only the named collection examples or care principles, not authentication of shop stock or claims of religious efficacy.