Gemstones

List of Gemstones A-Z with Characteristics

Below please find a comprehensive list A-Z of most common precious and semi-precious gemstones with their characteristics (chemical names, formula, colors, structure, and locations where to find them). List of...

Characteristics of Granite

Characteristics of Granite: Rock Type: Felsic, plutonic, igneous Major Minerals: Potassium feldspar, quartz, mica, sodium Minor Minerals: Sodium plagioclase, hornblende Colors: White, light grey, grey, pink, red Texture: Medium to...

Characteristics of Marble

Characteristics of Marble: Rock Type: Regional or contact metamorphic Structure: Crystalline Major Minerals: Calcite Minor Minerals: Diopside, tremolite, actinolite Colors: White, pink Texture: Fine to coarse   What is Marble? ...

Characteristics of Sandstone

Characteristics of Sandstone: Rock Type: Continental, detrital, sedimentary Fossils: Vertebrates, invertebrates, plants Major Minerals: Quartz, feldspar Minor Minerals: Silica, calcium carbonate Colors: Cream to red Texture: Fine-to medium-grained, angular to...

Characteristics of Limestone

Characteristics of Limestone: Rock Type: Marine, chemical, sedimentary Fossils: Marine and freshwater invertebrates Major Minerals: Calcite Minor Minerals: Aragonite, dolomite, siderite, quartz, pyrite Colors: White, grey, pink Texture: Fine to...

Characteristics of Obsidian

Characteristics of Obsidian: Chemical Name: Silicon dioxide Formula: Composed of SiO2, MgO and Fe3O4 Colors: Black, red, brown Structure: Amorphous Hardness: 5-6 Specific Gravity: 2.35-2.60 Refractive Index: 1.45-1.55 Lustre: Vitreous...