A contents policy will normally have a standard limit for valuables. You may be able to increase this if required. The policy will have a single article limit for each item claimed. If you have any expensive items, it would be wise to specify these on your policy. If they are not specified and are valued at more than the single article limit you will only receive the single article limit and therefore you will not receive the full amount.
Valuables are only covered for the general events such as theft, etc. They are not covered for accidental loss whether this is inside or outside the home. If you need this cover then you would need to select personal belongings cover and again you may want to specify them if they are expensive.
A general definition of valuables is:
Stamp, coin or medal collections, pictures, other works of art, items of gold, silver or any other precious metal, jewellery, watches and furs. Please check your policy booklet to check what your insurer refers to under this category.