Chrysoprase

Extended geology

Chrysoprase is a variety of chalcedony, the microcrystalline form of quartz, crystallizing in the trigonal system. Nickel-bearing minerals weather and alter in laterite and serpentine deposits, producing zones enriched in nickel that color the chalcedony green. The color comes from nickel held as finely dispersed nickel oxide and nickel silicate rather than within the quartz lattice, creating the characteristic apple to mint green. Metal concentration varies with deposit and location within a single deposit, producing natural color variation across pieces and within specimens.

Chrysoprase forms in shallow weathering profiles of nickel-rich rock, particularly in tropical and subtropical regions. The stone is always worked from larger rough pieces rather than occurring as natural terminations. This massive form is universal and does not limit the stone's beauty or craft potential. Hardness is 6.5 to 7 on the Mohs scale, the same as other chalcedony, making it suitable for jewelry wear. Specific gravity runs 2.58 to 2.64. The stone shows a waxy to slightly oily luster when polished and is translucent to semitransparent in thinner sections.

Color stability

Natural nickel-colored chrysoprase holds its color well in normal indoor light, but long exposure to strong sunlight or heat can fade it. If you want to preserve vibrant color, keep it out of direct sun when you are not wearing or using it.

Dyed chalcedony or dyed agate imitations may also fade or shift in tone with prolonged sunlight, so fading alone is not a test for authenticity. Some artificially colored stones are designed to be fade-resistant, but even those rarely achieve the warmth and natural depth of nickel-colored chrysoprase.

Extended sourcing

Marlborough, Queensland, Australia produces the world's premier chrysoprase. The district has been mined since the 1960s and supplies the majority of premium chrysoprase globally. The Australian material is known for consistent apple-green color, excellent translucency, and stable supply. Mining is small-scale and hand-sorted, with extraction methods designed to preserve the gemmy character of the rough. Documentation of origin is standard for Australian Marlborough material.

Poland's chrysoprase comes from deposits in lower Silesia, particularly the Szklary area. Polish material tends toward paler, slightly more yellowish-green tones compared to Australian stone. The character is respected in the international trade and fully natural. Supply is steady but smaller than Australia's.

Brazil produces chrysoprase from Goiás and Minas Gerais, with color ranging from pale mint to medium green. Brazilian material is less familiar in North American retail but is genuine and entirely natural. Central Tanzania is another established commercial source, and other deposits exist in Russia and California.

Authentication and testing

Genuine chrysoprase shows warm apple-green to mint-green color with natural variation. The stone is translucent in thin sections, feels smooth and slightly oily when polished, and shows subtle mottling or color shifts reflecting formation. Hardness sits at 6.5 to 7, scratching glass and feldspar. A steel knife will not scratch genuine chrysoprase.

Dyed imitations show artificially vivid, uniform color with no variation. They often appear glossy or shiny in a way natural chrysoprase does not. Some show concentric banding typical of agate rather than the subtle chalcedony character of real chrysoprase. Dyed pieces turn up at every price point, so judge the stone itself.

The most practical test is simple observation. Genuine chrysoprase carries warmth and subtlety in its color. Dyed stones look too perfect and too bright. If a piece shows no color variation or looks artificially uniform, it's likely not natural chrysoprase.

Pricing and market notes

Grade A tumbled chrysoprase is the entry point, with price rising with size. Hand-polished and faceted pieces sit higher. Palm stones and larger carvings scale upward from there, depending on origin and finish. High-quality Australian Marlborough material commands premium pricing; Polish and Brazilian material is typically more affordable.

Price alone proves nothing about natural status. Small, modestly priced chrysoprase can be entirely genuine, and dyed imitations can carry any price, so color, translucency, and origin disclosure are the real checks. At the top end, a higher price often reflects exceptional artistry, carving work, or rare origin rather than the mineral itself.

Warning signs: chrysoprase sold without origin disclosure, material claimed to be "rare" or "museum grade" when it's commercially available, pieces showing no natural color variation despite claims of natural status, and unusually bright or uniform green that looks artificial.