6 lbs is still within yorkie standard. Do you have a picture? Silkies are usually bigger and have longer snouts and bigger heads/faces. I have a friend who has an unmistakable silkie (9-10lbs) with a huge snout and big head with huge floppy ears (he's the sweetest and cutest dog), and she swears she has his lineage and papers, and he has champion bloodlines. I don't want to be mean by disagreeing but he is most definetely a silkie. To me, yorkies and silkies look SO different. Really the only thing they have in common in my view, is their coloring and that they are a small breed. But 6.2 lbs is still considered a yorkie unless he has a long face/snout. Sometimes vets and other people are often confused about the difference. Your baby is loveable either way though
