Definition of botryoidal in English:

botryoidal

adjective

  • (chiefly of minerals) having a shape reminiscent of a cluster of grapes.

    • ‘Malachite is typically massive, forming thick, compact crusts with botryoidal or mammillary surfaces and related stalactitic growths, all typically characterized by somewhat fibrous, color-banded interiors.’
    • ‘It is typically seen in collections as colorful botryoidal, reniform, or stalactitic masses or in crystalline encrustations.’
    • ‘If carried to completion, the growth results in a spherical form and the botryoidal or reniform habit.’
    • ‘Accessory minerals include earthy aggregates of clay minerals and botryoidal or stalactitic manganese oxides.’
    • ‘Recently, attractive though slightly damaged masses of botryoidal azurite and associated minor malachite have reached the collector market from a locality given as Seabra, Bahia, Brazil.’
    • ‘The photos show that the material is extremely fine grained and relatively featureless in plain light; in crossed nicols it gives a botryoidal effect similar to that seen in chalcedony.’
    • ‘This is a late-formed mineral that occurs as thin botryoidal crusts with little visible crystal structure.’
    • ‘Radiating to branching crystal groups and rounded, globular, reniform, and botryoidal masses are common.’
    • ‘Azurite commonly occurs in stalactitic, botryoidal, or earthy masses, many of which display concentric or parallel banding of various shades of blue or alternating with malachite.’
    • ‘Pale blue botryoidal masses and small rhombohedra somewhat similar to material from the Kelly mine, New Mexico, occurred in the Silver Hill mine, Waterman district, Pima County.’
    • ‘I collected lots of olive-green botryoidal pyromorphite on quartz matrix.’
    • ‘The first is massive, typically banded, botryoidal to stalactitic malachite from the great copper belt in the Shaba region, Democratic Republic of Congo.’
    • ‘Typically, crystals were not well-shaped but occurred as botryoidal crusts.’
    • ‘Some of the finer material crystallizes on botryoidal pectolite in the junction pockets.’
    • ‘Yellow botryoidal masses of mimetite associated with pyromorphite were once recovered from the Santa Rosa mine, Mazapil, and good specimens of yellow to orange mimetite have been found at La Blanca, Ojo Caliente, Zacatecas.’
    • ‘Another type of sphalerite is the botryoidal variety schalenblende, which occurs sparingly in one zone of the Sawatch Quartzite.’
    • ‘They can be separated into three distinct groups of authigenic carbonates, including a first stage with botryoidal aragonite, a second stage of clotted micrite, and a third stage of blocky spar.’
    • ‘It forms spherical clusters of tightly packed radiating crystals and botryoidal crusts.’
    • ‘Colorless botryoidal smithsonite specimens have been collected at the Tui mine, New Zealand.’
    • ‘Fibrous, botryoidal, stalactitic, granular, and massive varieties are common.’

Origin

Late 18th century: from Greek botruoeidēs (from botrus ‘bunch of grapes’) + -al.

Pronunciation

botryoidal

/ˌbɒtrɪˈɔɪd(ə)l/