Chains and necklaces
This overview is based on a survey of the online databases available from the national museums of Denmark, Norway and Sweden. In addition an overview of female grave finds from Denmark has been used.
These can be single, double or triple rings, or spirals. These are all made from bronze or other copper alloys. The quality varies from the obvious homemade to nice saw-cut rings. The single ring type can be the Rolo link where the rings are broad rather than being made from a thread. These are also made from bronze. Rolo links are high quality and only used for decorative purposes. The simple home made versions are found as working chains attaching various tools to brooches, the high quality chains are also found as pure decoration.
Spiga or Wheat chain
This is a variation on the simple ring chain. Here the links are oval and the chain is made from two interlinked simple chains that are offset from each other. Both bronze and silver examples are known.
These are the typical working chain, used for suspending various tools from brooches. Always made from bronze. Ranging from simple versions from thin wire (homemade?) to think links made from rod bronze. There are also several variations on the shape and examples where each link connects not only to the nearest neighbours but also the next-nearest neighbours. This makes the overall look varying from loose to dense.
Except from one find made of gold, necklaces of this type are all made from silver, and it is the most common type of silver necklace. These links give a distinct look, and again the links can be open weaved – only connecting to its neighbours, or dense weave – connecting to several other links. The simplest chains look homemade and more as a way of storing the silver rather than for decoration. The thick weaved links all have distinct tool marks on them indicating that the wire has been produced in the same way. The denser weaves where each link interconnect with both neighbouring links and next nearest neighbouring links (4 in 1) looks very similar to the spiga or Wheat type chains made from twisted oval links that are connected 4 in 1. Distinguishing between Spiga chain, U-shaped ovals and Viking wire weave can be quite hard.
This type of links are also used on larger iron chains.
In general if you are considering a chain that is not one of the above styles, it is strongly recommended to contact a member of the authenticity team for a discussion, or you risk that you will not be allowed to wear it during opening hours. Below is a list of chain styles that are known to be inauthentic.
Despite the name, there is no evidence that this chain pattern was used in the Byzantine empire. There is also no archaeological evidence for it in any of the Norse regions. According to The Metropolitan Museum of Art  it originates in the Eastern Javanese culture.
This covers a range of chains that all somehow resembles snake scales. Most of them are obviously modern, but a few look similar to wire weave, and are sometimes sold as 'Viking' but they originate from Bali.
To be completed by Jeppe