Mixed Minerals — Marin Mineral

Mixed Minerals
March 31, 2026 · 14 specimens

R886 - Rhodochrosite with Quartz $1,600 available

Sweet Home Mine, Alma, Colorado, USA
Thumbnail - 2.7 x 2.5 x 1.8 cm

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Translucent to transparent rhombs of Rhodochrosite shot through with crystals of Quartz. The Quartz crystals extend out in all directions, some doubly-terminated. The Rhodo rhombs reach 1cm in size.

R887 - Gold sold

Round Mountain Mine, Nye Co., Nevada, USA
Miniature - 4.2 x 3.3 x 3.3 cm

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Bright crystallized Gold with a large, flat front display face of crystals. Areas of Quartz and more Gold extend out the back side. Weighs 26.67 grams

R888 - Rose Quartz sphere sold

Madagascar
Small Cabinet - 6.7 x 6.7 x 6.7 cm

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Polished, asterated Rose Quartz sphere. Sometimes called 'Star Rose Quartz' this sphere exhibits a six-rayed star (asterism) when illuminated, caused by tiny, aligned rutile or borosilicate needle inclusions (see video).

R889 - Rose Quartz sphere sold

Madagascar
Miniature - 4 x 4 x 4 cm

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R891 - Benitoite sold

Gem Mine, San Benito Co., California, USA
Thumbnail - 2 x 2 x 1.3 cm

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Single blue Benitoite crystal on white Natrolite. The crystal is 1.3cm in size and highly transparent at the termination.

R892 - Rhodonite $500 available

Morro da Mina mine, Conselheiro Lafaiete, Minas Gerais, Brazil
Thumbnail - 2 x 2 x 1.8 cm

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Single gem crystal of Rhodonite on Calcite from recent finds in Brazil. This is an undamaged, complete 1.4cm crystal on matrix, which is uncommon as they are usually loose single crystals. Most of these have irregular, stepped terminations - this one has nice flat termination faces. Superb color.

R893 - Spinel $200 available

Luc Yen, Yen Bai Prov., Vietnam
Miniature - 3.2 x 2.5 x 2 cm

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Cluster of translucent red Spinel crystals from recent finds in Vietnam. The larger is a spinel-law twinned crystal, the smaller has octahedral form. The color is excellent for the find with a deep pure red.

R894 - Rhodochrosite stalactite $2,300 available

Capillitas Mine, Catamarca Prov., Argentina
Large Cabinet - 17 x 6 x 6 cm

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Large single stalactite of Rhodochrosite polished on the cut end. Big and heavy specimen with a smooth exterior on one half and crystals covering the other half. Ex. John Dabney collection.

R895 - Afghanite $600 available

Ladjuar Medam, Sar-e Sang, Koksha Valley, Badakshan, Afghanistan
Small Cabinet - 8.5 x 5.5 x 5.5 cm

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Highly translucent deep blue Afghanite crystals on matrix. The crystals reach 1.5cm in size and are almost gemmy. Small crystals of Pyrite and Phlogopite are scattered on the matrix. Ex. Len Pisciotta collection.

R896 - Malachite after Azurite sold

Sacramento Mine, Bisbee, Cochise Co., Arizona, USA
Small Cabinet - 7.5 x 6.5 x 6.5 cm

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Sharply formed crystals of Malachite pseudomorphs after Azurite filling vugs on matrix. A neat specimen with vugs along all sides when you turn it. Excellent, high quality crystals to 3.5cm. Interesting, colorful piece. Ex. John V. Mitchell collection dating back to the 1920s.

R897 - Prehnite sold

Merelani Hills, Arusha, Tanzania
Miniature - 4.3 x 3.5 x 2.3 cm

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Glassy, translucent Prehnite crystals in a uniform, hemispherical formation. Beautiful crystals with bright lemon yellow color. The base is flat and partially coated by Graphite. Ex. Mike Keim collection. I have bought hundreds of these over the years, this was one of my keepers.

R898 - Chabazite on Prehnite with Tanzanite $400 available

Merelani Hills, Arusha, Tanzania
Small Cabinet - 5.4 x 4.2 x 3.4 cm

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Glassy, translucent Prehnite crystals in tall ridge-like formation (better transluceny than photos depict). Beautiful crystals with bright yellow/green color. The front side is partially covered by Chabazite crystals. The backside has an attached large, paritall Tanzanite crystal. Ex. Mike Keim collection. I have bought hundreds of these over the years, this was one of my keepers.

R899 - Prehnite with Graphite rod $400 available

Merelani Hills, Arusha, Tanzania
Small Cabinet - 5.3 x 5 x 2.7 cm

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Glassy, translucent Prehnite crystals in a hemispherical formation. Beautiful crystals of yellow color. This started as a relatively smooth, round cluster that can still be seen in areas, with larger toothy crystals to 2cm grown out from the earlier cluster. There is also an unusual rod-like formation of Graphite that extends all the way through the cluster, which I've never seen before. Ex. Mike Keim collection. I have bought hundreds of these over the years, this was one of my keepers.

R900 - Prehnite sold

Merelani Hills, Arusha, Tanzania
Miniature - 4.3 x 3.5 x 2.3 cm

(click on an image to enlarge)

Cluster of translucent yellow/green Prehnite crystals. This started as a relatively smooth, round cluster that can still be seen in areas, with larger crystals grown out from the earlier cluster. Ex. Mike Keim collection. I have bought hundreds of these over the years, this was one of my keepers.

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