A druzy is sets of tiny crystals of minerals that form on the surface of another stone. There are many types of druzy, because there are many types of minerals. Each type of druzy has particular characteristics, such as crystal size, luster and color.
Amethyst is the world's most popular purple gem. It is the purple color variety of quartz that has been used in personal adornment for over 2000 years. It is used to produce faceted stones, cabochons, beads, tumbled stones, and many other items for jewelry and ornamental use. Amethyst has a Mohs hardness of 7 and does not break by cleavage. That makes it durable enough for use in rings, bracelets, earrings, pendants, and any type of jewelry.
One of the most impressive specimens of citrine that you might encounter is a large citrine geode from Brazil. Almost all citrine geodes are discovered with amethyst inside, but are heat treated to convert the purple amethyst into orangy brown citrine.
Lepidolite is the name of a rare lithium-rich mica mineral that is usually pink, red, or purple in color. It is the most common lithium-bearing mineral and serves as a minor ore of lithium metal, with rubidium and cesium sometimes being byproducts. When impregnated with quartz, lepidolite is used as a minor gemstone. Flakes of lepidolite are sometimes responsible for the color of pink and red aventurine.
The main gem form of Spodumene is Kunzite, the other is the rarer Hiddenite. Yellow and colourless gem forms of Spodumene also exist, but are not commonly faceted as gemstones. Kunzite has a lovely pink colour and is becoming increasingly popular in the gemstone market. The most important deposits of kunzite are from Minas Gerais, Brazil.
Watermelon tourmaline is one of the most popular types of Tourmaline which displays green, pink, and white color all in just one crystal that makes people think of a watermelon.