It is made using the collectible 'English Style': with punchy, bright colours rendered in clean, opaque bands. An Antique German Handmade 'Solid Core' Marble. Antique marbles in the solid core class are always a sought-after variety because of their charming colours and structure - they usually have a clear glass matrix with a decorative surround, encompassing the central solid core which usually reaches from top to bottom.
