oolites

/UW1 L AY0 T S/
noun
  1. 1

    A rock consisting of spherical grains within a mineral cortex accreted around a nucleus, often of quartz grains.

  2. 2

    An ooid or oolith.

Source: https://en.wiktionary.org/wiki/oolite, https://en.wiktionary.org/wiki/oolites