Jade (likely Nephrite or Jadeite)

Hardness: Nephrite 6-6.5, Jadeite 6.5-7 (Mohs scale). Color: Typically green (various shades), but can also be white, yellow, lavender, black, or reddish-brown. Luster: Vitreous to greasy. Crystal Structure: Monoclinic, forms as cryptocrystalline aggregates (fibrous in nephrite, granular in jadeite) giving it exceptional toughness. Cleavage: Poor in nephrite (due to fibrous nature), fair in jadeite. Specific Gravity: Nephrite 2.9-3.1, Jadeite 3.3-3.5.

Jade forms under conditions of high pressure and relatively low temperature metamorphism. Nephrite is typically found in altered ultrabasic rocks (serpentinites) and often in contact with granitoids. Jadeite forms in subduction zone metamorphic environments. Both types can be found as alluvial boulders and pebbles in riverbeds, or in situ within metamorphic rocks. Geological age varies depending on the specific deposit, ranging from hundreds of millions to tens of millions of years old.

Predominantly used as a highly valued gemstone for jewelry (beads, cabochons, carvings) and ornamental objects. Historically, it has been used for tools, weapons, and ritualistic items due to its exceptional toughness. In some cultures, particularly in East Asia, it holds immense cultural and spiritual significance.

The term "jade" refers to two distinct minerals, nephrite and jadeite, which were not distinguished as separate minerals until 1863. Jadeite is often considered the higher-quality and more valuable of the two, particularly the intense emerald-green variety known as 'Imperial Jade' from Myanmar. The stone's remarkable toughness makes it difficult to carve, requiring abrasive techniques rather than cutting.

In the field, distinguishing true jade from common imitations (like serpentine, quartz, prehnite) requires experience. Look for its characteristic waxy to vitreous luster, cool-to-the-touch feel, and exceptional toughness (it's very difficult to scratch or break). Common locations include Myanmar (Jadeite), China, New Zealand, Russia, Canada, United States (California and Wyoming), and Guatemala. For collectors, assessing quality involves evaluating color saturation, translucency, texture, and the presence of any inclusions or fractures. The beads in the image display typical light to medium green hues with some translucency, consistent with polished jade.