I wondered if you had all read about this before? It seems to me a similar process to the making of a cane?
If not, this is an extract from a book written in 1852 Dodd, The curiosities of the industry and applied sciences. The author was writing about mosaics made of glass and went on to write about a description made in the 18th century of two glass mosaic pieces (not known what era the mosaic referred to were made but the authors he talks about obviously made their description in the 18th century):
'The two specimens of glass mosaic decribed by Winckelmann and Count Caylus in the last century, seem to have been of a somewhat different kind, for they presented a complete picture on each surface. They consisted of coloured glass fibres fitted together with the utmost exactness, and cemented by fusion into a solid mass. Of these two specimens, each of which was about an inch long by a third of an inch broad one exliibited, on a dark ground of variegated colours, a representation of a duck; the outlines were decided and sharp, tlie colours beautiful and pure, and the effect veiy stiiking, from tlie artist having combined opaque with transparent glass; the most delicate pencil of the mmiature painter could not have traced more accurately and distinctly, either the circle of the pupil of the eye, or the apparently scaly feathers on the breast and wings. The other specimen was about the same size, and exhibited an ornamental device of green, white, and yellow colours, which were traced on a blue ground, and represented volutes, beads, and flowers. On whichever side these specimens were viewed a similar object was perceived; for the pictures were fonned of veiy slender fibres of glass, laid side by side, according to tlieir colours, and afterwards exposed to a heat just sufficient to fuse the whole into a cemented mass, without disturbing or injuring the tints of any one fibre.'