Vintage 4.5” Niloak Blue Brown Vase mineralized stamp

Description

Niloak 4.5" swirl vase, marked mineralized on the bottom.  No other marks.  The name Niloak is marked on the bottom of most pieces except that manufactured and sold in the state of Colorado as a native product.  I found info that says at this time it is not know when Niloak Pottery made these wares for retail in Colorado.
**The last photo shows a mark that looks like a pencil mark on the top, I have no idea what it is.**  I've had this vase for a few years and have only wiped it with a dry cloth, inside may have some dust.  I am thinking if you are looking at this auction that you know far more than I do about this vase.
If you have any questions let me know.
Smoke free home.
Please remit payment at auctions end.
Shipping to the US only, M - F.
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