Menilite from Sahara desert North Africa
Size-
16.5cm x 10.1cm x 7.4cm
Weight-
1655g
You will receive the item in the photo
Menilite is an opaque grayish-brown or earthy variety of common opal. Because it is a form of opal mixed with various impurities,its classification bridges the gap between a mineraloid and sedimentary rock.
Crystal system- It has no Crystal system because it is amorphous. As a variety of opal, it is classified as a mineraloid rather than a true mineral. It lacks a repeating long range internal crystalline structure. Its macroscopic form is microcrystalline to non-crystalline,typically manifesting smooth,rounded or bulbous masses known as Botryoidal concretions.
Mineral class- silicate specifically sitting within the Tectosilicate subgroup as a variety of opal. Chemically it consists of hydrated silicon dioxide heavily intermixed with sedimentary impurities like clay,dolomite, or calcite giving it its characteristic matte pebble-like exterior.
Rock formation- Menilite is biologically and chemically classified as a sedimentary rock concretion. It forms as nodules or layers within sedimentary beds rich in organic matter,such as shales,marls,diatomaceous earth and gypsum deposits.
It is created when silica rich fluids precipitate and cement together within sedimentary layers. Because it often originates in low energy marine or lacustrine environments,it frequently traps clay,calcium carbonate and microfossils during its growth.
