Jewelry-making
Etsy
Description: This is kind of an obvious one, but I'm including it for the sake of completion. The Craft Supplies section of Etsy can be such a great place to get things like charms, crystals, cabochon settings, and beads.
MTS Arts & Crafts
Description: Has a great selection of Swarovski crystals, beads, chains, tools, epoxy, findings etc. If they don't have it they'll know who might.
CooksonGold
Description: Aimed towards professional jewellery making, has diamonds, sapphires, metals, swarovski, clay-metal etc. Delivery to Malta is cheap (depending on order placed) and quick.
House of Trimmings
Description: Smaller selection than MTS or JB but can have hidden gems (pun intended)
JB stores Haberdashery (Level 3)
Description: Their Haberdashery is huge and generally my first port of call for anything. Staff is helpful and creative too so can help with suggestions and options they have available.