looks like a body hammer that didn't grow up.

about 7 inches  across

Jeweler's?

aug184 by Skip Albright, on Flickr

That is a beauty!!!

Could be a whitesmith's hammer.

Maybe it's a Cross Peen Pin Hammer for carpenters driving small pins.  You would use the cross peen for starting a small pin or brad to avoid mashing your fingers.

What's a whitesmith ?

I goggled whitesmith and answered my question, I worked with metal since the late 60's and I've never heard that term before,

There's a pattern of cabinetmaker's hammer called Warrington, with that same cross peen on one side, striking face on the other.  Some of the small ones get delicate (my eight ounce one is a sweet little thing), but I've never seen one this delicate before, so this may not be one of those.  Still, this looks like Alberto Giacometti's* Warrington hammer.
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For those not familiar with Alberto Giacometti, this is one of his sculptures:

looks like a super skinny Warrington to me, too.   

Hello, Was the Warrington hammer also called a "Joiner's Hammer" ? Regards, Lou

The "Cross Peen Pin hammer" was used by carpenters, joiners, pattern makers or anyone that had to drive small pins, brads or clips, sometimes called a telephone hammer.  A google search of "Cross Peen Pin hammer" will show images of hammers just like the one in the OP.

Here is an Amazon link..       https://www.amazon.com/Silverline-Tools-Hardwood-Cross-Hammer/dp/B000LFVBPC

Quote from: lptools on August 13, 2020, 05:09:20 AM
Hello, Was the Warrington hammer also called a "Joiner's Hammer" ? Regards, Lou

I found references to "English pattern joiner's hammer" showing that style.

Hello, Bill. Thanks, I know that I have seen/heard the term before.I had never heard "Cross Peen Pin Hammer", I learned something new today. Here is a link to a company that calls this "style" a Joiner's Hammer. Not as nicely made as the one skip posted!!!! Regards, Lou


https://www.tigersupplies.com/Products/English-Pattern-Joiners-Hammer__PIC0008701-125-.aspx

Personally, I like "Warrington," for its historical reference.

0008701-125: 0.2 lbs Head Weight, 10" Handle Length, 16 mm Face
0008701-150: 0.3 lbs Head Weight, 11" Handle Length, 18mm Face
0008701-180: 0.3 lbs Head Weight, 11" Handle Length, 20mm Face
0008701-240: 0.5 lbs Head Weight, 12" Handle Length, 22mm Face
0008701-300: 0.6 lbs Head Weight, 12" Handle Length, 25mm Face
0008701-450: 0.9 lbs Head Weight, 12" Handle Length, 28mm Face


I have yet to figure a way to weigh heads while the handle is still on


Skip

Find a handle or head real close to the ones you have. Weigh the hammer, or head ,then subtract the  weight. It won't be exact, but should do.