Grape Agate

Ironstone Concretion are rounded mineral formations found in sedimentary rock layers, primarily composed of iron compounds. Formed under specific chemical conditions, they accumulate around a nucleus like a leaf or bone. Often rusty-brown or reddish, these dense formations can range from small nodules to large boulders. They might resemble fossils externally and can even encase real fossils internally. Found globally in rocks like sandstones and shales, they intrigue rock collectors and can be used decoratively when polished.

The primary interest in goethite is as an ore of iron; it is otherwise not very attractive as a mineral specimen. High concentrations of goethite have been found in the United States; other, less significant finds have been spotted in Mexico and Canada.

Orthoclase is a feldspar mineral and one of the most common rock-forming materials in Earth's crust. It is usually encountered within different types of granite, where it is responsible for the pinkish or lighter flecks in that rock. The iridescent gemstone known as moonstone is also a variant of orthoclase.

Goshenite is a colorless to white variety of beryl, making it less attractive than other highly valued beryl varieties like emerald and aquamarine. Due to its lack of color, goshenite has never become popular in the gem market and is mostly prized by collectors.

Most often found in metamorphic rock, actinolite is a fibrous mineral that is a very rare type of asbestos. One variety of the material is nephrite, which is a form of jade. There is also a rare and highly sought catseye version of the mineral. Industrial asbestos is sometimes made from certain varieties of actinolite.

The color and clarity of dioptase are quite stunning; however, it is infrequent to find any specimen larger than fragmented crystals. A fist-sized specimen is a real find! This mineral is incredibly fragile and can break at the slightest jostle. Surprisingly, when dioptase is heated, it releases an electric charge.

Slate is a fine-grained, metamorphic rock that is created when shale or mudstone is altered by the heat and pressure of metamorphic action. Most slate is gray in color. Its durability and physical appeal make it a popular material for roofing and flooring. It is also used to build school blackboards and even pool tables.

Chondrodite is a relatively rare mineral that occurs in transparent or translucent shades of yellow, brown, or red in small rounded grains. This mineral is brittle and may be found alongside marble as well as other metamorphic rocks. Chondrodite is a member of the Humite group which contains several nesosilicates.