Smyckena var bland värdesakerna.

Because smyckena is the definite plural form of smycke.

The forms are:

• ett smycke = a piece of jewelry / an ornament
• smycken = pieces of jewelry / ornaments
• smyckena = the pieces of jewelry / the ornaments

In Swedish, definiteness is usually added as an ending, instead of using a separate word like the.

So:

• smyckena = the jewelry items / the jewels

Var is the past tense of är.

These are forms of att vara = to be:

• är = is / are
• var = was / were

So:

• Smyckena är bland värdesakerna = the jewelry is among the valuables
• Smyckena var bland värdesakerna = the jewelry was among the valuables

For the same reason: it is also a definite plural noun.

The base noun is en värdesak = a valuable / a valuable object.

Its forms are:

• en värdesak = a valuable
• värdesaker = valuables
• värdesakerna = the valuables

So both nouns in the sentence are definite plural:

• smyckena = the jewelry items
• värdesakerna = the valuables

Because the sentence is talking about specific, known things, not jewelry and valuables in general.

Swedish uses the definite form when the speaker and listener are understood to know which things are meant.

So this sentence is not about jewelry in general. It is about the specific jewelry and the specific valuables in some context, for example in a list, a police report, or an inventory.

Because Swedish usually expresses the by attaching it to the noun as a suffix.

Examples:

• bok = book

• boken = the book

• hus = house

• huset = the house

• smycken = jewelry items
• smyckena = the jewelry items

So instead of saying something like the valuables, Swedish says värdesakerna.

The dictionary forms are:

• smycke for smyckena
• värdesak for värdesakerna

When looking up Swedish nouns, you usually want the singular indefinite form:

• ett smycke
• en värdesak

That is the form dictionaries normally list.

Not exactly.

In English, jewelry is usually an uncountable noun. You normally do not say two jewelry. You say:

• some jewelry
• pieces of jewelry

In Swedish, smycke is a normal countable noun:

• ett smycke = one piece of jewelry
• två smycken = two pieces of jewelry

So smyckena often means something like:

• the pieces of jewelry
• the jewels
• the jewelry items

This is a very common difference between English and Swedish.

Bland is a preposition. Here it means among or amid.

So:

• bland värdesakerna = among the valuables

It shows the relationship between the jewelry and the valuables.

Common examples:

• bland barnen = among the children
• bland pappren = among the papers
• bland gästerna = among the guests

Normally, no.

• bland means among a group of things
• i means in or inside

Since värdesakerna refers to a collection of valuable objects, bland is the natural choice: the jewelry was among the valuables.

Using i would sound odd unless you were talking about being physically inside something.

This is normal Swedish main-clause word order:

• subject: Smyckena
• verb: var
• adverbial/prepositional phrase: bland värdesakerna

So it follows the common pattern:

• Subject + verb + other information

Very straightforward.

Yes, that is possible.

Swedish allows another element to come first for emphasis. If you start with Bland värdesakerna, the verb still comes second:

• Bland värdesakerna var smyckena.

This version emphasizes where they were.

Compare:

• Smyckena var bland värdesakerna.
  Focuses more naturally on the jewelry.

• Bland värdesakerna var smyckena.
  Focuses more on among the valuables.

Both are grammatical.

Both can be possible, but they are slightly different.

• var = was/were; a neutral statement of location or situation
• låg = lay; emphasizes physical position

So:

• Smyckena var bland värdesakerna.
  A neutral statement: the jewelry was among the valuables.

• Smyckena låg bland värdesakerna.
  More concrete: the jewelry was lying among the valuables.

Swedish often uses position verbs such as ligga, stå, and sitta, but vara is also common when the exact physical position is not important.

Unfortunately, this usually has to be learned with the noun.

You should memorize them as:

• ett smycke
• en värdesak

Their plural forms also help a bit:

• ett smycke → smycken → smyckena
• en värdesak → värdesaker → värdesakerna

There is no completely reliable rule that lets you guess every noun’s gender, so learning the article together with the noun is the best habit.

They use different plural patterns:

• smycke → smycken
  Here the plural is formed with -n

• värdesak → värdesaker
  Here the plural is formed with -er

Then the definite plural adds -a or -na, depending on the pattern:

• smycken → smyckena
• värdesaker → värdesakerna

So this sentence is also a good reminder that Swedish nouns do not all form the plural in the same way.