[4] In some parts of Australia they are also widely known as "Christmas spiders" because they are most numerous during the summer months (December and January).

[10][11] The generic name is derived from Latin auster ("south") and Greek ἄκανθα (ákantha, "thorn").

[1][15] The five subspecies of Austracantha minax are the following:[1][15] Jewel spiders have a distinctive appearance that makes them relatively easy to identify.

The maxillae and other mouthparts are black at the base, lightening to brown and bright yellow at the tips.

[22] The opisthosoma (abdomen) is large, slightly wider than it is long, and strongly rounded at the front and back.

Like all mature male spiders, they are relatively easy to identify because of their greatly enlarged pedipalps used in sperm transfer during mating.

[25] Jewel spiders found later in autumn (from March to April) are also sometimes melanistic, being entirely dark brown to black in colouration.

[25] For example, it has been speculated that the purpose of the melanistic colour morphs may be to facilitate better heat absorption during the colder months.

[6][16] They are circular with a very dense spiral pattern woven around twenty to thirty rays attached to support threads.

[16] Jewel spiders are unusual in that they deliberately make their support threads visible to larger animals.

[33][34] They can often be found living near each other in large overlapping aggregations of orb webs of usually thirty individuals.

A 1997 study observed that aggregations do not seem to increase the amount of prey caught, but it is believed that they still benefit the individual members in other ways.

The female will respond by moving towards the source of the vibrations, eventually climbing unto the mating thread itself.

[24][33] A female jewel spider can mate with multiple males during a single reproductive cycle.

To prevent sperm competition, the successful male will defend the female shortly before and after mating.

It actively drives away other rival males until the female enters a refractory period and ceases to be receptive to further matings.

This usually happens an hour to a day after a successful mating, during which the female will herself aggressively attack and drive away all courting males.

[33] Females usually attach their egg sacs on vegetation and other surfaces near the edges of their webs (including grass blades, leaves, and twigs).

[16][37] The egg sacs are around 15 to 35 mm (0.59 to 1.38 in) in length and can vary in shape from circular to pointed at both ends.

[7][10][41] When disturbed, they will try to escape by clambering upside down along their support threads to nearby surfaces (albeit slowly due to their short stubby legs).

[26][37] Like almost all spiders, they possess venom glands which they use to subdue prey, but they rarely bite when handled.

[7][10][21] In Perth and the rest of Western Australia, the appearance of jewel spiders in large numbers in gardens (as well as the flowering of Nuytsia floribunda) is often associated with the coming of Christmas.