Quattrocento Y Cinquecento

Minerals

Quartz
Quartz is the second most abundant mineral in the Earth's continental crust, after feldspar. Quartz forms part of the silicate group. It is found in almost every geological environment and is at least a component of almost every rock type. Throughout the world, varieties of quartz have been of the most common used minerals in the making of jewelry and hardstone carvings.Quartz has a unique structure. Actually, there is another mineral that shares quartz's structure, and it is not even a silicate. It is a rare phosphate named berlinite.
Quartz is used to represent 7 in Mohs Scale. Mohs Scale is used to measure the hardness of minerals.

Some types of quartz are:
* Rock crystal
* Amethyst
* Citrine
* Rose quartz
* Rutilated quartz
* Milkquartz
* Smoky quartz

Beryl
Beryl is often one of the minerals that people do not know about. However, it is one of the most important gem minerals. Beryl is colorless in pure form; it is the many different impurities that give beryl its varied coloration. Without these splendid color varieties, beryl would be an ordinary gemstone with only some brilliance. Emerald is the green varietyand Aquamarine is the blue variety of beryl.
Other colors of beryl are also used as gemstones but are not as well known.
* The greenish-yellow variety is called Heliodor.
* The pink variety is called Morganite.
* The colorless variety is called Goshenite.
* The name beryl is used for the red and golden varieties, which are simply called red beryl and golden beryl.
Emerald is highlyprized and is one of the most valued gemstones. Aquamarine is also a popular gem although it is not as expensive as emeralds.



Aquamarine Emerald

Corundum
When someone talks about the most famous gemstones such as diamond, topaz, aquamarine, emerald and garnet, corundum does not usually get mentioned. However, its twovarieties are sure to be on any list of gemstones. The red variety of corundum is known as ruby and all the other colors of corundum are known as sapphire. The rare colorless or white crystals are called corundum in the mineral world, but artificial colorless plates of corundum are called sapphire and used as watch faces. That's because a sapphire crystal sounds much more valuable than a corundumcrystal.
Corundum is the third hardest natural mineral known to science. The hardest mineral, diamond is still four times harder than corundum. The second hardest is Moissanite at 9.25 barely beats corundum's hardness of 9.0. The hardness of corundum can be caused by the strong and short oxygen-aluminum bonds. These bonds pull the oxygen and aluminum atoms close together, making the crystal not onlyhard but also quite dense compared to other minerals.

Pure Corundum Ruby (Red Corundum)

Fluorite
Fluorite is a mineral with a huge variety of brilliant colors. Fluorite is well known and prized for its glassy luster and rich variety of colors.
The colors for fluorite (in order of most common) are:
* Purple
* Blue
*Green
* Yellow
* Colorless
* Brown,
* Pink,
* Black
* Reddish orange
Fluorite is also known as “The Most Colorful Mineral in the World.”
The many colors of fluorite are truly wonderful. The rich purple color is by far fluorite's most famous and popular color. It is also compared with the beautiful purple of amethyst.
The blue, green and yellow varieties offluorite are also deeply colored, popular and attractive. The colorless variety is not as popular as the colored varieties, but their rarity still makes them interesting for collectors. The rarer colors of pink, reddish orange (rose) and even black are usually very attractive.

Purple Fluorite

Gypsum
Gypsum is one of the most common minerals in sedimentary environments. Since it forms...