A 1 gram microdose of fresh magic truffles is often estimated to contain about 0.5 to 2 mg of psilocybin, with around 1 mg as a rough average. The exact amount can vary by batch.
Potency depends on species, growing conditions, harvest timing, and especially freshness. Psilocybin can degrade after harvest, so cool, dark, dry storage helps preserve it.
The precise content in your truffles cannot be verified without lab testing, and other compounds like psilocin, baeocystin, and norbaeocystin may influence perceived strength. For background, see this psilocybin overview.
Hope this clarifies the typical range.