silver and chrysoprase Pin / Pendant ~ Arts and Crafts style

Obviously a studio-made piece, this sterling silver and green stone combination pin / pendant I would categorize as an Arts and Crafts piece if the hallmark didn't throw me off. There are several questions about it that vex me. Its stone looks very much like chrysoprase to me but it registers in the "jadeite / spinel" area of my gem-tester. And even though I would easily say it's period Arts and Crafts, it is marked with an old style "925" hallmark in raised numerals set within a rectangular reserve. Yet, if I am not mistaken, this type of numeric hallmark for sterling was not used until much later in the 20th c., except if we are dealing with Mexican jewelry which does not seem to be the case here. All questions set aside, I have to draw your attention to the tiny little three-petal flowers adorning the brooch's top and bottom and the simple but so effective way of etching a halo of sun-rays around the green freshness of the stone...

Size / Weight: 1 5/8" tall by 1 1/4" wide; 16.1 grams

Hallmarks / Date: simply marked "925" as shown; 1960s?

Condition: excellent vintage with a beautiful, semi-translucent stone, minimal yet quite effective decoration, nice patina and no damage or unsightly repairs noted except maybe a replaced pin in the clasp that is not silver

Inv# 14647