Erythrite

Erythrite or red cobalt is a secondary hydrated arsenate of cobalt minerals with the formula (Co3(AsO4)2·8H2O). Erythrite and annabergite (Ni3(AsO4)2·8H2O) (nickel arsenate) form a complete series with the general formula (Co,Ni)3(AsO4)2·8H2O. Hardness: 1.5-2.5 on the Mohs scale of hardness.Luster: (In crystals) Adamantine to vitreous, but pearly on cleavage. (As a crust) Earthy.Specific Gravity: 3.06.Cleavage: {010} Perfect.Erythrite crystallizes in the monoclinic system and forms prismatic crystals. The color is crimson to pink and occurs as a secondary coating known as cobalt bloom on cobalt arsenide minerals. Well-formed crystals are rare, with most of the mineral manifesting in crusts or small reniform aggregates.
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Noun
1. a reddish mineral consisting of hydrated cobalt arsenate in monoclinic crystalline form and used in coloring glass; usually found in veins bearing cobalt and arsenic
(synonym) cobalt bloom
(hypernym) mineral

(n.)
A rose-red mineral, crystallized and earthy, a hydrous arseniate of cobalt, known also as cobalt bloom; -- called also erythrin or erythrine.
  

(n.)
A colorless crystalline substance, C4H6.(OH)4, of a sweet, cooling taste, extracted from certain lichens, and obtained by the decomposition of erythrin; -- called also erythrol, erythroglucin, erythromannite, pseudorcin, cobalt bloom, and under the name phycite obtained from the alga Protococcus vulgaris. It is a tetrabasic alcohol, corresponding to glycol and glycerin.
  

General Information:
 Chemical Formula:
Co3(AsO4)2·8(H2O)
 Composition:
(Molecular Weight = 598.76 gm)
Cobalt 29.53 % Co
Arsenic 25.03 % As
Hydrogen 2.69 % H 
Oxygen 42.75 % O 
 Empirical Formula:
Co3(AsO4)2·8(H2O)
 Name Origin:
Named from the Greek, erythros for "red."
Physical Properties:
 Cleavage:
[010] Perfect
 Color:
colorless, violet red, light pink, or purple red.
 Density:
3.06 - 3.18, Average = 3.12
 Diaphaniety:
Transparent to subtranslucent
 Habits:
Striated - Parallel lines on crystal surface or cleavage face., Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline)., Divergent - Crystals radiate from a center without producing stellar forms.
 Hardness:
1.5-2 - Talc-Gypsum
 Luminescence:
None.
 Luster:
Pearly
 Streak:
pinkish red
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erythrite
danh từ (khoáng chất) erythrit
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