LYC’s Crystal Dictionary Word Index

Gems By LYC
4 min readSep 12, 2022


This is an ongoing index of the terms used throughout the crystal dictionary, if there is a word you're looking for that isn’t indexed yet, comment, and it will be updated swiftly

Abiogenic petroleum formation — a fringe science which proposes that most of earth’s petroleum and natural gas deposits were formed inorganically

Amulet — Worn as protection in order to ward off evil

Basal — Forming or belonging to a bottom layer or base

Birefringence — The numerical difference between the refractive indices of a mineral. This difference results in a display of interference colors when thin sections or small fragments of anisotropic minerals are viewed between crossed polars

Charm — Anything used to attract good luck

Chemical Classification — A system that attempts to classify elements or compounds according to certain chemical functional or structural properties

Chemical Formula — A set of chemical symbols showing the elements present in a compound and their relative proportions, and in some cases the structure of the compound

Chemical Name — The name of a chemical compound that shows the names of each of its elements or sub-compounds

Chemical Structure — A determination that includes a chemist’s specifying the molecular geometry and, when feasible and necessary, the electronic structure of the target molecule or other solid, and basically refers to the way atoms are arranged within molecules

Chemical System — chemical mixtures comprising a network or set of interacting molecules (Example: A plant where photosynthesis occurs)

Chirality or Chiral — an object or molecule cannot be superimposed on its mirror image by any translations or rotations

Classification — the action or process of classifying something according to shared qualities or characteristics

Cleavage — The tendency of minerals to split along crystallographic planes as a result of structural locations of atoms and ions in the crystal, creating planes of relative weakness

Conchoidal — Denoting a type of fracture in a solid (such as flint or quartz) that results in a smooth rounded surface resembling the shape of a scallop shell (Example: Black Obsidian)

Crystal — A crystal or crystalline solid is a solid material whose constituents are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions

Exsolution — A process through which an initially homogeneous solid solution separates into at least two different crystalline minerals without the addition or removal of any materials

Lapidary — relating to stone and gems and the work involved in engraving, cutting, or polishing

Lattice Points — a point at the intersection of two or more grid lines in a regularly spaced array of points

Luminescence — The emission of light by a substance that has not been heated, as in fluorescence and phosphorescence

Luster — Describes how a mineral appears to reflect light, and how brilliant or dull the mineral is. The terms used to describe luster are:

  • Metallic (aka splendent)
  • Submetallic
  • Vitreous (aka glassy)
  • Adamantine (aka brilliant or diamond-like)
  • Resinous (aka resin-like)
  • Silky
  • Pearly (aka mother-of-pearl)
  • Greasy (aka oily)
  • Pitchy (aka pitch-like)
  • Waxy (aka wax-like)
  • Dull (aka earthy)

Parting — occurs when minerals break along planes of structural weakness due to external stress, along twin composition planes, or along planes of weakness due to the exsolution of another mineral

Talisman — Used to attract something specific to the owner. They are consecrated and charged with a lot of energy to help fulfill their intended use

Tectosilicate — Formerly called a polysilicate, any member of a group of compounds with structures that have silicate tetrahedrons (each of which consists of a central silicon atom surrounded by four oxygen atoms at the corners of the tetrahedron) arranged in a three-dimensional lattice. Tectosilicate minerals make up nearly ¾ of the Earth’s crust, and are made up of little tetrahedrons of the very common elements silicon and oxygen

Tenacity — refers to a mineral’s toughness or resistance to breaking or being deformed. Brittle, as their molecules are held together by weak ionic bonds. Therefore, these minerals shatter when they’re struck. Malleable, as they are easily hammered into different forms. Metallic minerals, such as copper and gold

Transparency — A way of describing how much light, if any, a gem can transmit and how scattered that light is when it exits the gem

Zoning — A texture developed in solid-solution minerals and characterized optically by changes in the color or extinction angle of the mineral from the core to the rim



Gems By LYC

Gems By LYC strives to inform crystal enthusiasts of the proper knowledge of their gemstones and provide quality and affordable gemstones.