Agate (/ˈæɡ.ət/)
Agate, the gemstone, came in many forms and colors, most of which were considered ornamental stones or hardstones in the Realms. It is a common rock formation consisting of Chalcedony and Quartz, with a wide variety of colors.
Agates are primarily formed within volcanic and metamorphic rocks. The ornamental use of agate was common in many ancient cultures, in assorted jewelry and in the seal stones of fallen warriors, while bead necklaces with pierced and polished agate date back to a time long past.
See Also Gems and minerals related to agates:
Description
Agates were a form of Chalcedony, which made them part of a large family of gems and minerals.Varieties
Common varieties in the Realms included:See Also Gems and minerals related to agates:
Properties
Material Characteristics
Types
Lace agate is a variety that exhibits a lace-like pattern with forms such as eyes, swirls, bands or zigzags. Blue lace agate is especially hard. Crazy lace agate is often brightly colored with a complex pattern, demonstrating randomized distribution of contour lines and circular droplets, scattered throughout the Rock. The stone is typically coloured red and white but is also seen to exhibit yellow and grey combinations as well. Moss Agate, as the name suggests, exhibits a moss-like pattern and is of a greenish colour. The coloration is not created by any vegetative growth, but rather through the mixture of Chalcedony and oxidized Iron hornblende. Dendritic agate also displays vegetative features, including fern-like patterns formed due to the presence of manganese and Iron oxides. Turritella agate (Elimia tenera) is formed from the shells of fossilized freshwater Turritella gastropods with elongated spiral shells. Similarly, Coral, Petrified Wood, porous rocks and other organic remains can also form agate. Coldwater agates did not form under volcanic processes, but instead formed within the limestone and dolomite strata of marine origin. Like volcanic-origin agates, Coldwater agates formed from silica gels that lined pockets and seams within the bedrock. These agates are typically less colorful, with banded lines of grey and white Chalcedony. Greek agate is a name given to pale white to tan colored agate often used it for making jewelry and beads. Brazilian agate is found as sizable geodes of layered nodules. These occur in brownish tones inter-layered with white and gray. It is often dyed in various colors for ornamental purposes. Polyhedroid agate forms in a flat-sided shape similar to a polyhedron. When sliced, it often shows a characteristic layering of concentric polygons. It has been suggested that growth is not crystallographically controlled but is due to the filling-in of spaces between pre-existing crystals which have since dissolved. Iris Agate is a finely-banded and usually colorless agate, that when thinly sliced, exhibits spectral decomposition of white light into its constituent colors, requiring 400 to up to 30,000 bands per inch. Other forms of agate include Holley blue agate (also spelled "Holly blue agate"), a rare dark blue ribbon agate; Lake Superior agate; Carnelian agate (has reddish hues Botswana agate; plume agate; condor agate; tube agate containing visible flow channels or pinhole-sized "tubes"; fortification agate with contrasting concentric banding reminiscent of defensive ditches and walls around ancient forts; Binghamite, a rare variety; Fire Agate showing an iridescent, internal flash or "fire," the result of a layer of clear agate over a layer of hydrothermally deposited Hematite; Patuxent River stone, a red and yellow form of agate; and enhydro agate, which contains tiny inclusions of water, sometimes with air bubbles. Agate is a beautiful and versatile gemstone that is often used in jewelry making. It is a type of Chalcedony, a mineral in the Quartz family, and is known for its colorful, banded patterns and wide range of hues. Here are a few reasons why agate makes amazing jewelry:- Durability: Agate is a relatively hard and durable gemstone, which makes it a good choice for jewelry that will be worn frequently or subjected to rough handling. It has a Mohs hardness rating of 6.5-7, which means it is resistant to scratching and chipping.
- Versatility: Agate comes in a wide range of colors, including shades of red, orange, yellow, green, blue, purple, and pink, as well as black and white. This makes it a versatile choice for a wide variety of jewelry styles and color schemes..
- Metaphysical properties: Agate is believed to have grounding and stabilizing properties, and is often used to promote balance, harmony, and calm. It is also said to enhance mental function and increase energy..
- Affordability: Agate is generally more affordable than other gemstones, which makes it a good choice for those on a budget..
Physical & Chemical Properties
Formation and properties
Agate minerals have the tendency to form on or within pre-existing rocks, creating difficulties in accurately determining their time of formation. Their host rocks have been dated to have formed as early as the Archean Eon. Agates are most commonly found as nodules within the cavities of volcanic rocks. These cavities are formed from the gases trapped within the liquid volcanic material forming vesicles. Cavities are then filled in with silica-rich fluids from the volcanic material, layers are deposited on the walls of the cavity slowly working their way inwards. The first layer deposited on the cavity walls is commonly known as the priming layer. Variations in the character of the solution or in the conditions of deposition may cause a corresponding variation in the successive layers. These variations in layers result in bands of Chalcedony, often alternating with layers of crystalline Quartz forming Banded Agate. Hollow agates can also form due to the deposition of liquid-rich silica not penetrating deep enough to fill the cavity completely. Agate will form crystals within the reduced cavity, and the apex of each Crystal may point towards the center of the cavity. The priming layer is often dark green, but can be modified by Iron oxide resulting in a rust like appearance. Agate is very durable, and is often found detached from its host matrix, which has eroded away. Once removed, the outer surface is usually pitted and rough from filling the cavity of its former matrix. Agates have also been found in sedimentary rocks, normally in limestone or dolomite; these sedimentary rocks acquire cavities often from decomposed branches or other buried organic material. If silica-rich fluids are able to penetrate into these cavities agates can be formed.History & Usage
Everyday use
Cultural Significance and Usage
The decorative arts use it to make ornaments such as pins, brooches or other types of jewellery, paper knives, inkstands, marbles and seals. Agate is also still used today for decorative displays, cabochons, beads, carvings and Intarsia art as well as face-polished and tumble-polished specimens of varying size and origin. Agates have long been used in arts and crafts. There are churches who have even used it as window panes.
Industrial Use
Industrial uses of agate exploit its hardness, ability to retain a highly polished surface finish and resistance to chemical attack. It has traditionally been used to make knife-edge bearings for laboratory balances and precision pendulums, and sometimes to make mortars and pestles to crush and mix chemicals.
Type
Mineral
Value
8 sp - 10 gp
Rarity
Common
Color
banded