Dolomite?

[BridgetownTreasures]

Is this specimen dolomite? Not sure about the copper-colored flecks and the crystal (fluorite?)
Thanks!!

 

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[ToddsPoint]

Dolomite is a sedimentary limestone. Your rock looks like anything but limestone. It looks more like a breccia or a conglomerate. Gary

 

[galenrog]

Dolomite can be one of two rock types. First is a calcium magnesium carbonate, which can express itself as crystals and crystalline formations.

Second, and perhaps more common in the rock collecting and lapidary hobbies, is a sedimentary carbonate composed mostly of dolomite. When this type has dendritic inclusions, and can be polished to a high sheen, it is sometimes referred to as White Buffalo.

Now that we have the short definitions out of the way, your sample does not resemble any sample of dolomite I have ever seen. While not certain of what it is, I lean toward the opinion of ToddsPoint.

Time for more coffee.

 

[BridgetownTreasures]

Thank you! Any ideas about the metal and the larger crystal?

 

[galenrog]

No idea. You could take it to a university geology department, if you have one nearby that is willing to identify samples from the public. Also, many rock and mineral clubs have a wealth of knowledge between their members. Field rock and mineral guides are always helpful. I probably have between ten and twenty dog eared guides that go with me on road trips.

Time for more coffee.

 

[Steve1236]

Cerussite with barite? Just a wild guess after looking online at different images, what ever it is that's a really cool specimen in my opinion.

 

[Ponchosportal]

Dolomite with chalcopyrite crystals. Larger crystal is calcite.

 

[fuss]

Where is this from?

 

[BridgetownTreasures]

Most of grandpa’s collection is local to Oregon. Could have been a more distant find though.

It’s a neat little piece. There are those yellow crystals dispersed throughout, in addition to the large one on the end.

The reason I thought dolomite is that the white crystals are rough and brittle, almost like coral. I’m a complete novice, but it looked a bit like some dolomite specimens I see in the field guide.

The metallic flakes range from a pyrite color to a darker copper.

 

[DDancer]

The trigonal crystals remind me of sphalerite, a zinc ore. Gonna take some digging on it....