Description Diamine Tyrian Purple fountain pen ink is a plummy shade of purple. Diamine ink is considered to be well behaved and smooth flowing, and comes in an 80ml glass bottle with a narrow neck and square base. Diamine fountain pen ink has been made in the UK for over 150 years. Having trouble deciding between colors? Use our Ink Comparison Tool to quickly and easily view different colors side by side. We offer Free Shipping on all orders over $59 for US customers, and for orders over $250 for our Canadian customers.