Rare, excellent quality, antique 17th century ca. 1650 Italian or French

Rare, excellent quality, antique 17th century, circa 1650, Italian or French aristocrats' stiletto dagger with a beautifully faceted agate stone hilt.
Steel crossguard comprising a rectangular quillon block, finely hand-chiseled on both sides, with acanthus leaves, turned quillons with knob terminals hand-chiseled with leaves en suite to the block, slender tapered blade of stiff diamond section with a baluster ricasso.
This is the best quality you can get with a 17th-century stiletto that I have seen in my 50 years of involvement in collecting and trading antique arms and armor. During these years, I have never seen that particular style of dagger called a Gunner's Stiletto; in any museums, private collections, or references,  made to such quality with a finely carved steel crossguard, finely cut semiprecious stone agate grip, and an extremely well-executed blade.

My reference library on arms and armor includes books and museum catalogs from around the world printed in the 19th, 20th, and 21st centuries.
I found such a high-quality dagger in none of these sources, including the major reference on the subject from the Metropolitan Museum of Art in New York "Catalog of European Daggers Including the Ellis, De Dino, Riggs, and Reubell Collections" by Bashford Dean, published by the Metropolitan Museum of Art, New York, 1929.

A fantastic museum quality piece from the 17th century suitable for royalty.
CONDITION: In very good original untouched condition, for a 350-year-old stiletto. The crossguard and the ricasso retain traces of gold gilding.
MEASUREMENTS
Overall length: 25.5 cm (10.04 inches)
REFERENCES:
"Catalog of European Daggers 1300-1800: Including the Ellis, de Dino, Riggs, and Reubell Collections" by Bashford Dean, published by the Metropolitan Museum of Art, New York, 1929.