Gemology: D is for ...

When it comes to gemstones beginning with D, we all know Diamonds! But there are several more less-well known gemstone quality minerals beginning with D which can be just as beautiful, and in some cases even more valuable. Take a journey through the colourful world of gems beginning with D here.

Danburite Danburite is a clear crystal though it can also occur in shades of yellowish brown giving it an appearance similar to topaz. At the moment it's relatively unknown, but stay tuned - we predict this attractive little gem will be growing in popularity!

Image Attribution: Rob Lavinsky, iRocks.com – CC-BY-SA-3.0 [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

Datolite

A pale green mineral gemstone, – though occasionally occurring in pinks – Datolite can be highly sparkly or vary through to opaque. It's somewhat brittle so not ideally suited to jewellery manufacture, but it can make a pretty ornamental piece for a desktop or home office.

Image Attribution: Rob Lavinsky, iRocks.com – CC-BY-SA-3.0 [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

Demantoid Demantoid is the most expensive member of the garnet family but unlike the garnet you may be more familiar with, this particularly valuable garnet is bright green. First discovered in Russia in 1868, Demantoid doesn't occur in large stones with stones over 2 carats being extremely rare. Unlike the majority of stones where inclusions can lower the value, the tiny inclusions of asbestos (looking like horsetails) that naturally occur in Demantoid can increase the value significantly.

Image Attribution: By shakko (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

Diamond

Everyone is familiar with diamond! An intensive marketing campaign in the 1930s saw diamond rise to a meteoric popularity as an engagement ring, and the trend shows no signs of slowing down any time soon. Diamond is the hardest naturally occurring substance known to man, and only another diamond can cut a diamond. Diamond is actually pure carbon, but in this particular form it has been crushed under immense pressure to form the beautiful clear gemstone we all know and love. Diamond can also naturally occur in other colours, known in the jewellery world as 'fancy diamonds', and for those lucky people born in April, Diamond is your birthstone!

Diopside

Diopside is formed in magma (lava flow), with few crystals being worthy of cutting into gemstones. Those Diopside crystals that are gem-worthy form in green crystals which can vary from transparent to opaque with chatoyancy (cat's eye effect) forming a four=pointed star.

Image Attribution: By Didier Descouens (Own work) [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons

Dioptase

Dioptase is a copper silicate mineral with a strikingly similar appearance to Emerald in its green form, though it also occurs in blue-green.

Image Attributes: Rob Lavinsky, iRocks.com – CC-BY-SA-3.0 [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

Dravite Dravite is the name given to brown tourmaline. It's not particulary desirable as a gemstone but a few locations produce crystals with a good lustre and colour. Colours vary from yellow, through orange to brown and brownish-black.

Dumortierite Dumortierite forms as an inclusion within quartz. It frequently occurs in shades of blue, but occasionally has been found in pinks and purples too. Dumortierite is not particularly desirable as a gemstone because of its flat colour and dullness, which is a pity because it has a great hardness and workability to it.

Next week: "Know Your Birthstones ~ A Fun Month-by-Month Guide". What's your traditional birthstone? Is it different from your modern birthstone? Our fun guide to birthstones will tell you why we have them, what they are, and what strange magical superstitions and healing powers are attached to each!