Is it a good idea to Itemize/Group/Schedule valuable items such as card collections on your homeowner policy?  Yes, it is.  The reason is it's valuable and anything of value such as $10,000 Wedding Ring or Baseball Card collection is worth protecting.  In the event of a loss to a Itemized/Grouped/Scheduled jewelry item the claim becomes much easier to settle as you have a qualified appraisal which sets a value.  Without a appraisal a policyholder is limited as to ability to produce documentation of lost/stolen item(s).  Some insurance companies will allow blanket for a group of coin collections, card collections or jewelry/silverware.   
Blanketing means you may not have any recent appraisal; however, you have items of value.  One of my companies permits blanket grouping up to $50,000; however there is a $5000 per item maximum and has $500 deductible per loss which is better than homeowner policy deductible which are usually higher such as $1000 or $1500.  Without an appraisal this is best way to obtain "some" coverage for your valuables.  
Another item is photos or possibly keeping valuable items in a fire proof safe.  
For further information please contact Flanigan Insurance at dflanflanins@yahoo.com or 314-727-6000.