Harrach Seaweed pattern pink & silver mica art glass vase

This was a super find at the bi - monthly antiques fair, a lovely example of Harrach's Seaweed pattern.
The vase is made from three layers of cased glass, clear over deep pink & silver mica, with an opaline white interior.
It measures 15.5 cm tall, 5 cm across the cupped top rim, & 5 cm across the base.
I really like the shape of this, the four lobed base is nicely balanced by the cupped top.
I'd love to know how they managed to get the mica inclusions to form the seaweed pattern...
Bohemian origin, late 19th century.