Question
We were given a beautiful bonsai as a gift last October and recently the needles have begun to shed and the color has faded. It has been watered almost daily and has been placed on a window to receive about 2-3 hours of direct sun every day.

We're worried that out lovely tree will not survive without expert help.

I can send a picture of the bonsai if that is possible on this site.

We believe that the bonsai is a variety of juniper, and has little clusters of short sharp needles.

Answer
Most of these comercial bonsai junipers are sold as being indoor plants when in fact they need to be outdoors.  Your watering schedule is to much and the tree is too wet.  Don't water until it starts to dry out.  If it has rocks glued to the surface of the soil remove them.

You should also be aware that most of these junipers do not survive because by the time the owner decides they have a problem the tree is in really bad shape and usually beyond salvation.  That's why this is the tree of choice for some of these unscrupulous growers, the tree can be dead for six months before it starts to look dead.  I hope I am wrong here but don't get your hopes up.  

The tree needs to go outdoors if possible, watered only when it starts to dry out and have the rocks removed from the soil surface.  Put it in a location where it gets a good deal of sun.

Vance Wood.