I was making a map with version 15w34a and summing a Armor Stand with invisible on and head with mossy cobblestone but in 15w34a the block head doesn't appear. Here is command
/summon ArmorStand ~ ~ ~ {Invisible:1,Equipment:[{},{},{},{},{id:stonebrick,Damage:1,Count:1}]}
WAI. Per MC-85544, the equipment tag is now deprecated. Use HandItems and Armor Items instead.