Solid Opal

Solid

Solid is a state of matter in which atoms are closely packed and are difficult to move past each other. Solids resist compression, expansion, or external forces that would alter its shape, with the degree of resistance being dependent upon the specific material under consideration. Solids also always possess the least kinetic energy per atom/molecule relative to other phases or, equivalently stated, solids are formed when matter in a fluid phase is cooled below a certain temperature. This temperature is called the melting point of the substance and is an intrinsic property; i.e. independent of how much of the matter there is. The vast majority of substances, when in the solid state, can be arranged in one of a few ubiquitous structures.

Opal

Opal is a hydrated amorphous form of silica (SiO2·nH2O); its water content may range from 3% to 21% by weight, but is usually between 6% and 10%. Due to the amorphous (chemical) physical structure, it is classified as a mineraloid, unlike crystalline forms of silica, which are considered minerals. It is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, marl, and basalt.

solid

Adjective

1. That can be picked up or held, having a texture, and usually firm. Unlike a liquid, gas or plasma.
2. Appreciably large in size, quantity, or value.

Adverb

1. Solidly.
2. Without spaces or hyphens.

opal

Noun

1. A mineral consisting, like quartz, of silica, but inferior to quartz in hardness and specific gravity, of the chemical formula SiO2·nH2O.