Crisoprasa
Cuarzo is a mineral with formula SiO₂, in the Silicatos [Tectosilicatos (Grupo Cuarzo)] group. This specimen comes from Szklary, Ząbkowice Śląskie, Baja Silesia (Dolnośląskie), Frankenstein, Polonia and joined the Terrium collection in 1998.
Description
Flat piece with a rough white, earthy matrix. A continuous band of chrysoprase of very saturated apple‑green colour appears within, more intense in the centre and slightly more translucent towards the margins. Surface with waxy lustre and fine fracture typical of chalcedony. Gemmological classification: chrysoprase, gem grade, intense green colour (fine/intense green).
History of this specimen
On 30 November 2025, after talking about chrysoprase and variscite, I found that Aleydis was not a woman, as I had always thought, but a man. In his collection this piece carried the number 176, which I have kept as a reminder of this anecdote and as a mark of respect—to this great fellow.
About Cuarzo
Chrysoprase is the most valuable variety of the chalcedony group. Its green colour is due to inclusions of nickel silicates. Although it shares the formula of quartz (SiO₂), its structure is cryptocrystalline (a fibrous and microcrystalline aggregation).
About the locality
World reference and first documented locality for chrysoprase, mined since the Middle Ages together with nickel and other minerals, until complete closure in 1980. Many dumps remain in the area, though almost all are covered by very dense vegetation. They are called "the Frankenstein deposits", the historic name of the principal town, associated both with the novel "The Modern Prometheus" and with a real black legend. During the plague epidemic of 1606, a group of gravediggers exhumed corpses to make a "poisonous powder" and scatter it in houses, seeking to increase their work. They were caught and burned alive. It seems very likely that Mary Shelley was inspired by this event for her story. Incidentally: Frankenstein literally means "the stone of the Franks" (Franken = the Franks, Stein = stone).
Technical data
- Catalogue No.
- 0176
- Composition
- SiO₂
- Name
- Cuarzo
- Variety
- Calcedonia (Crisoprasa)
- Group
- Silicatos [Tectosilicatos (Grupo Cuarzo)]
- Category
- Meritum Persé
- Mine
- Szklary
- District / Municipality
- Ząbkowice Śląskie
- Province
- Baja Silesia (Dolnośląskie)
- Region
- Frankenstein
- Country
- Polonia
- Size (cm)
- 8 x 6.5 x 3
- Weight
- 227 g
- Acquired
- 1998
- Ex-collection
- Aleydis Soliveres
- Etymology
- From Greek "chrysos" (gold) and "prason" (leek), for its green colour.
- Quality
- Muy buena
- Value trend
- Estable
Related specimens
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- Cristobalita — Estados Unidos
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- Cuarzo (Cloritado) — Nepal
- Cuarzo — Portugal