An easier way to get shards?

[swamppride]

Can we not break crystals and clusters?

[Jojoya]

Can we not break crystals and clusters?

No, those can't be broken into shards. You're also going to need a fair number of those before you learn Aetherial Reduction so better to save them as you get them.

Additional sources of shards outside of retainer ventures, gathering and gardening are tradecraft/fieldcraft levequests and some of the Ixali beast tribe dailies. The numbers aren't huge per quest but they do add up.

Make certain to buy low level materials from vendors when you can. Frequently the price of the material is less than the value of the shards needed to craft them from raw materials (depending on your world's market prices). Even if it's slightly more expensive, it allows you to conserve your shards for crafting finished products or for making HQ materials when needed. Housing material suppliers and ARR beast tribe vendors are huge helps for most materials needed below level 35 (leathers, gems and culinarian supplies needed over level 15 being the notable exceptions).