Green porphyry is a semi-precious stone, known for its ornamental use throughout history, including in medieval altars. It has also been used since antiquity as a pigment. When dispersed in watercolor medium, green porphyry produces a gorgeous, bluish-green color with...

Red opalite is a semi-precious stone, also called "common opal," a geological relative to opal without the iridescent effect of its precious sibling. This red opalite was mined in Arizona, and it definitely calls to mind the red rock landscape...

Lapis lazuli, a brilliant blue gemstone used in artist paints since the Middle Ages, is one of the rarest and most romantic pigments in the world. This precious stone was once the only way of obtaining ultramarine, which is the...

From the Schmincke Vault: These special Horadam tubes were produced in 2018 for a limited edition of watercolors made from stone ground, semi-precious gemstones. Earlier this year, a cache of vintage stock from this edition was found in the stock...