cryptocrystalline

American  

[krip-toh-kris-tl-in, -ahyn] / ˌkrɪp toʊˈkrɪs tl ɪn, -ˌaɪn /

adjective

Mineralogy.

1. having a microscopic crystalline structure.

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cryptocrystalline British  

/ ˌkrɪptəʊˈkrɪstəlaɪn /

adjective

1. (of rocks) composed of crystals that can be distinguished individually only by the use of a polarizing microscope

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cryptocrystalline Scientific  

/ krĭp′tō-krĭs′tə-lĭn,-līn′ /

1. Having a microscopic crystalline structure, as the mineral chalcedony does.

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Etymology

Origin of cryptocrystalline

First recorded in 1860–65; crypto- + crystalline

Example Sentences

The ground-mass of these rocks is often micro-crystalline, with a web of minute felspars mixed with interstitial grains of quartz; but in many dacites it is largely vitreous, while in others it is felsitic or cryptocrystalline.

From Project Gutenberg

H�lleflinta under the microscope is very finely crystalline, or even cryptocrystalline, resembling the felsitic matrix of many acid rocks.

From Project Gutenberg

That is, the metamorphic rocks are characteristically holocrystalline, while igneous rocks are porphyritic, or cryptocrystalline.

From Project Gutenberg

In the cooling and crystallizing of igneous rocks from a state of fusion many minerals are formed, the most common being silicates of the alkaline earths, which are usually inclosed in a glassy or cryptocrystalline base.

From Project Gutenberg

Making Stone Points Points and blades chipped from cryptocrystalline rocks such as chert, flint, and obsidian make the sharpest knives, arrowheads, and spear tips, although efficiently using the latter two requires lots of practice.

From Time Magazine Archive