Keep provenance attached
A sample without a label quickly becomes a color or texture exercise. Record the supplier or source if known, product name, date received, dimensions, and finish. Do not invent missing information. "Unidentified stone, reclaimed sample" is an honest and useful description.
If the sample is part of a selection process, add the proposed location and the question it is meant to answer. A piece chosen to compare surface texture is not necessarily a verified example of the final product or batch. Keep those distinctions in the log.
Compare under shared conditions
Photograph samples in the same light with a neutral background and a scale. Avoid strong automatic filters. Rotate the pieces together so reflections do not favor one finish. Photos help with organization, but they do not replace the physical samples for color-critical work.
Record tactile observations separately from measurable information. "Feels cool and smooth" is an observation; a thermal value requires an appropriate source. Likewise, a hand-held sample cannot establish fire, acoustic, or slip performance. Refer to the product documentation and the intended assembly.
Leave room for change
Use a stable reference number that stays with the sample even if the selection changes. Add a status such as study, shortlisted, or superseded, and keep the reason for a change. Removing rejected options can erase the most useful part of the decision record.
Store samples so their labels remain legible and their edges do not damage neighboring pieces. Review the collection occasionally. A smaller, well-labeled reference set is more useful than a large shelf of attractive mysteries.