This is an addon to Glass Shards which makes ice and packed ice also drop shards when broken. These can be crafted back into ice or packed ice.
It also adds a Frozen Pickaxe which can harvest ice faster and prevents it from turning into water, so you don't make a mess when building with ice.
The drop chance is configurable separately from Glass Shards, and separately for regular and packed ice.
It has compatibility with other mods, just as well as Glass Shards.