Here is a classic Anda tektite from northwestern Pangasinan Province, Republic of the Philippines. This specimen shows the trademark bowtie or flower ornamentation reminiscent of rodent chew marks common to this region.
There are also Thailandites with Anda-like ornamentation (and they are often inappropriately offered on Ebay as “Anda tektites”; to merit the name genuine Andas must come from the Anda region!).
The peculiar ornamentation decorates both primary surfaces and, as seen in the second photo, old breaks and bubble interiors. The latter implies a terrestrial etching origin. I have noted differences in the average specific gravity of Anda and non-Anda Philippinites. The same contrast occurs in Anda-like Thailandites and their non-Anda-like counterparts, which hints at a possible compositional factor contributing to the ornamentation, the full explanation of which remains a mystery for me. (54.5 grams; author’s personal collection).